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Dr Xanthe Spindler

Image of Xanthe Spindler
Chancellor's Post Doctoral Research Fellow, School of Chemistry and Forensic Science
Core Member, Forensic Science Research Strength
B. Sc (Forensic)(Hons) (UNewcastle), PhD (UC)
 
Can supervise: Yes

Conferences

Chan, J.H., Stuart, B.H., Roux, C.P., Shimmon, R., Lennard, C.J. & Spindler, X. 2010, 'The synthesis of 1,4-anthraquinones and their application as fingermark detection reagents on porous surfaces', 20th International Symposium on the Forensic Sciences Abstract Book.
Chan, J.H., Shimmon, R., Spindler, X., Maynard, P.J., Lennard, C.J., Roux, C.P. & Stuart, B.H. 2009, 'Investigation into isatin and 1,4-anthraquinones as fingerprint detection reagents on porous surfaces', UTS Faculty of Science Research Day Book of Abstracts, pp. 1-1.

Journal articles

Chadwick, S.R., Xiao, L.H., Maynard, P.J., Lennard, C., Spindler, X. & Roux, C.P. 2014, 'PolyCyano UV: an investigation into a one-step luminescent cyanoacrylate fuming process', Australian Journal of Forensic Sciences, vol. 0, no. 0, pp. 1-14.
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PolyCyano UV (Foster?+?Freeman Ltd) is a new one-step process for developing luminescent fingermarks using cyanoacrylate (CA) fuming without the need for further chemical treatment. In this study, conditions including the amount of PolyCyano UV powder, the humidity level of the fuming chamber, and the time and temperature of the fuming process were optimised. A variety of different surfaces were tested and aged fingermark samples were also examined. The PolyCyano-UV-developed fingermarks were compared with conventional CA-developed fingermarks and subsequently stained with rhodamine 6G. PolyCyano UV was able to develop high-quality fingermarks on the surfaces tested. However, when examined under UV light, the luminescence of PolyCyano-UV-developed fingermarks was found to be weaker than conventional CA-developed fingermarks that were stained with rhodamine 6G. When used in sequence with rhodamine 6G, PolyCyano UV was found to give significantly improved contrast compared with conventional CA-developed fingermarks stained with rhodamine 6G.
de la Hunty, M., Spindler, X., Chadwick, S., Lennard, C. & Roux, C. 2014, 'Synthesis and application of an aqueous nile red microemulsion for the development of fingermarks on porous surfaces', Forensic Science International, vol. 244, pp. e48-e55.
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An oil-in-water microemulsion containing a luminescent dye, nile red, has been synthesised using a solvent-diffusion method. This has been demonstrated to be effective in developing fresh latent fingermarks on porous surfaces. The working solution is made using a binary surfactant solution to create a lactescent dual organic-aqueous phase intermediate, which subsequently results in a transparent microemulsion after the organic solvent has evaporated. The solution is non-toxic and performs comparatively with a previously published methanolic formulation but at a much lower cost and with an extended shelf life. The microemulsion outperforms a previously reported aqueous nile blue formulation for the development of both charged and natural fresh fingermarks, and requires lower exposure times for image recording.
Marriott, C., Lee, R., Wilkes, Z., Comber, B., Spindler, X., Roux, C. & Lennard, C. 2014, 'Evaluation of fingermark detection sequences on paper substrates.', Forensic Sci Int, vol. 236, pp. 30-37.
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It is generally accepted that the amino acid reagent consisting of 1,2-indanedione and a catalytic amount of zinc chloride, referred to as IND-Zn, is the single best method for the detection of latent fingermarks on paper substrates and that ninhydrin is of limited value when used in sequence after this reagent. However, recent research has suggested that the sequence 1,8-diazafluoren-9-one (DFO) followed by ninhydrin may actually produce a greater number of fingermarks than IND-Zn on its own or IND-Zn followed by ninhydrin. This study focussed on the evaluation of two fingermark detection sequences for porous surfaces: (1) IND-Zn followed by ninhydrin, physical developer (PD) and the lipid stain nile red; and (2) DFO followed by ninhydrin, PD and nile red. The evaluation was undertaken using a range of latent fingermark donors and on a number of paper substrates that are commonly encountered in Australia. In addition, a pseudo-operational trial was completed on 5-year-old university examination booklets. Parallel studies were undertaken at two locations: Sydney (temperate, coastal climate) and Canberra (relatively dry, continental climate). The results of the donor study indicated that there was a negligible difference in performance between the two sequences across all paper types and all time periods evaluated. When considering individual reagents, IND-Zn generally developed better quality fingermarks compared to DFO; however, ninhydrin had a greater enhancement effect on DFO developed marks than after IND-Zn. In the pseudo-operational trials, the IND-Zn sequence outperformed the DFO sequence. Nile red did not develop any additional marks at the end of each sequence and, as a result, the use of this technique at the end of a full sequence is of questionable value. The overall outcome was that the sequence IND-Zn followed by ninhydrin and PD is recommended for the processing of common paper substrates under the conditions typically experienced at the two locations studied.
Braasch, K., de la Hunty, M., Deppe, J., Spindler, X., Cantu, A.A., Maynard, P., Lennard, C. & Roux, C. 2013, 'Nile red: Alternative to physical developer for the detection of latent fingermarks on wet porous surfaces?', Forensic Sci Int, vol. 230, no. 1-3, pp. 74-80.
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This paper describes the application of a luminescent lipid stain, nile red, for the development of latent fingermarks on porous surfaces. An optimised formulation is presented that provides rapid development of latent fingermarks on porous surfaces that are or have been wet. A comparison with physical developer (PD), the method of choice to enhance such fingermarks, indicated that nile red was a simpler and more stable technique for the development of fingermarks. The nile red formulation showed similar performance to PD across a range of substrates and ageing conditions, although PD still showed greater sensitivity on five-year-old examination booklets used in a pseudo-operational study. The pseudo-operational trial also indicated that nile red consistently developed different fingermarks to those enhanced by PD, suggesting that it preferentially targets a different fraction of the latent fingermark deposit. Significantly, the compatibility of nile red in a detection sequence with indanedione-zinc, ninhydrin and PD is reported.
Wood, M., Maynard, P., Spindler, X., Roux, C. & Lennard, C. 2013, 'Selective targeting of fingermarks using immunogenic techniques', Australian Journal of Forensic Sciences, vol. 45, no. 2, pp. 211-226.
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Latent fingermark detection remains one of the most commonly utilised forensic practices when dealing with scenes of crime or related items. Although many options are available to detect and visualise these marks, the quest for techniques with greater sensitivity and selectivity continues. This has led to many improvements in detection methods and also numerous new techniques being developed. However, these have largely only led to incremental advancements despite the desire for transformational improvements. The use of immunology in the detection of latent fingermarks is an area that has been investigated more recently as a possible proposal to provide these transformational improvements, specifically to overcome sensitivity and selectivity issues currently seen with existing methods. This paper reviews the attempts to harness the detection capabilities of immunology and utilise them in the field of latent fingermark detection. Results achieved to date have highlighted many advantages and possibilities in detection and visualisation of latent marks, including the possibility of gaining intelligence from the marks themselves. This paper also presents a brief introduction to the use of aptamers as the next logical step in immunogenic techniques for investigation. 2013 Copyright Taylor and Francis Group, LLC.
Chadwick, S., Maynard, P., Kirkbride, P., Lennard, C., McDonagh, A., Spindler, X. & Roux, C. 2012, 'Styryl dye coated metal oxide powders for the detection of latent fingermarks on non-porous surfaces.', Forensic Sci Int, vol. 219, no. 1-3, pp. 208-214.
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Conventional fingermark powders rely on contrast induced by absorption/reflection (e.g. black powder) or luminescence in the visible region (e.g. Blitz Green()). In most cases, these powders provide sufficient contrast; however, in some circumstances surface characteristics can interfere with the visualisation of powdered fingermarks. Visualisation in the near infra-red (NIR) region, however, has been shown to eliminate interferences commonly encountered in the visible region. In this study, a mixture of rhodamine 6G and the NIR laser dye styryl 11 (STaR 11) was coated onto an aluminium oxide nanopowder and then mixed with silver magnetic powder to develop and visualise fingermarks in the NIR. When compared to Blitz Green(), it was determined that the STaR 11 magnetic powder was better suited for marks deposited on textured surfaces and for older marks, whereas Blitz Green() performed better on smooth glossy surfaces. The ability of the STaR 11 mixed dye formulation to be visualised in both the visible and NIR regions also provides a significant advantage over conventional luminescent fingermark powders.
Wood, M., Maynard, P.J., Spindler, X., Lennard, C.J. & Roux, C.P. 2012, 'Visualization of latent fingermarks using an aptamer-based reagent', Angewandte Chemie International Edition, vol. 124, no. 0, pp. 12438-12440.
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Don't touch! Aptamers selected against lysozyme are transformed into aptamer-based reagents, with which latent fingermarks can be developed with high selectivity and sensitivity. The design of aptamers targeting components of latent fingermarks opens up a new range of detection methods that previously have not been explored.
Montgomery, L.N., Spindler, X., Maynard, P.J., Lennard, C.J. & Roux, C.P. 2012, 'Pre-treatment strategies for the improved cyanoacrylate development of dry latent fingermarks on non-porous surfaces', Journal of Forensic Identification, vol. 62, no. 5, pp. 517-542.
Cyanoacrylate fuming is a popular technique commonly used by evidence examiners for the development of latent fingermarks on nonporous surfaces. The process involves the preferential formation of hard, white polycyanoacrylate along the ridgelines of the fingerprint as opposed to the substrate background. This preferential deposition results in contrast between the fingerprint and substrate. This contrast may be further enhanced through the use of staining techniques such as rhodamine 6G. Because the cyanoacrylate mechanism is believed to be initiated by fingerprint constituents and catalyzed by moisture, ii follows that fingerprints subjected to harsh conditions (e.g., heat, low humidity, or CV light) often produce poorly developed results. This study aimed to further investigate and validate the use of 10% w/v methylamine as a pretreatment strategy to overcome the limitations associated with the cyanoacrylate development of dry fingerprints and to compare the results with those obtained using previously proposed pretreatment solutions. The effectiveness of this treatment was demonstrated on samples similar to those encountered in casework, and scanning electron microscopy (SEM) of the treated fingerprints con- firmed the rejuvenation of the dry latent deposits through a qualitative assessment of the polymer morphology.
Montgomery, L.N., Spindler, X., Maynard, P.J., Lennard, C.J. & Roux, C.P. 2012, 'Pretreatment strategies for the improved cyanoacrylate development of dry latent fingerprints on nonporous surfaces', Journal of Forensic Identification, vol. 62, no. 5, pp. 517-542.
Cyanoacrylate fuming is a popular technique commonly used by evidence examiners for the development of latent fingermarks on nonporous surfaces. The process involves the preferential formation of hard, white polycyanoacrylate along the ridgelines of the fingerprint as opposed to the substrate background. This preferential deposition results in contrast between the fingerprint and substrate. This contrast may be further enhanced through the use of staining techniques such as rhodamine 6G. Because the cyanoacrylate mechanism is believed to be initiated by fingerprint constituents and catalyzed by moisture, it follows that fingerprints subjected to harsh conditions (e.g., heat, low humidity, or UV light) often produce poorly developed results. This study aimed to further investigate and validate the use of 10 percent w/v methylamine as a pretreatment strategy to overcome the limitations associated with the cyanoacrylate development of dry fingerprints and to compare the results with those obtained using previously proposed pretreatment solutions. The effectiveness of the proposed treatment was demonstrated on samples similar to those encountered in casework, and scanning electron microscopy (SEM) of the treated fingerprints confirmed the rejuvenation of the dry latent deposits through a qualitative assessment of the polymer morphology
Wood, M., Maynard, P., Spindler, X., Lennard, C. & Roux, C. 2012, 'Visualization of latent fingermarks using an aptamer-based reagent', Angewandte Chemie - International Edition, vol. 51, no. 49, pp. 12272-12274.
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Don't touch! Aptamers selected against lysozyme are transformed into aptamer-based reagents, with which latent fingermarks can be developed with high selectivity and sensitivity. The design of aptamers targeting components of latent fingermarks opens up a new range of detection methods that previously have not been explored. Copyright 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Spindler, X., Shimmon, R., Roux, C. & Lennard, C. 2011, 'The effect of zinc chloride, humidity and the substrate on the reaction of 1,2-indanedione-zinc with amino acids in latent fingermark secretions.', Forensic Sci Int, vol. 212, no. 1-3, pp. 150-157.
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Anecdotal evidence from forensic practitioners and studies conducted under controlled conditions have indicated that the reaction between 1,2-indanedione and the amino acids present in latent fingermark deposits is highly susceptible to ambient humidity. The addition of catalytic amounts of zinc chloride to the 1,2-indanedione working solution--usually in the order of 1:25 to 1:4 molar ratio (indanedione:zinc)--significantly improves the colour and luminescence of fingermarks treated under dry conditions but appears to have a negligible effect on fingermarks treated in humid environments. The results presented in this paper confirmed that zinc(II) ions added to the 1,2-indanedione working solution act as a Lewis acid catalyst, stabilising a key intermediate during a rate-limiting hydrolysis step. Furthermore, studying the reaction using a chromatography-grade cellulose substrate method previously reported confirmed that cellulose substrates play a major role in facilitating the indanedione-amino acid reaction by acting as a surface catalyst in the early stages of the reaction and by directing the formation of the desired luminescent product (Joulli's Pink).
Chadwick, S., Maynard, P., Kirkbride, P., Lennard, C., Spindler, X. & Roux, C. 2011, 'Use of Styryl 11 and STaR 11 for the Luminescence Enhancement of Cyanoacrylate-Developed Fingermarks in the Visible and Near-Infrared Regions', Journal of Forensic Sciences, vol. 56, no. 6, pp. 1505-1513.
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Abstract: In current casework, most post-cyanoacrylate stains rely on luminescence emission in the visible region (400-700nm). While traditional stains such as rhodamine 6G work well under most circumstances, some surfaces may generate background luminescence under the same conditions. Detection in the near-infrared region (NIR>700nm) has shown to be effective in minimizing the interferences from such surfaces. The laser dye styryl 11 generated strongly luminescent fingermarks when applied after cyanoacrylate fuming on all surfaces tested. When compared to rhodamine 6G, the dye was superior only when viewed in the NIR. Styryl 11 was subsequently combined with rhodamine 6G, and the mixed stain formulation (named StaR 11 by the authors) induced stronger luminescence compared with styryl 11 alone with an ability to visualize in both the visible and NIR regions. Reliable and consistent results were obtained when using either styryl 11 alone or the STaR 11 mixture. The enhancement achieved did not otherwise vary depending on the source of the fingermark secretions. With visualization possible in both the visible and NIR regions, the styryl 11/rhodamine 6G mixture showed significant potential as a post-cyanoacrylate stain. 2011 American Academy of Forensic Sciences.
Fung, T.C., Grimwood, K., Shimmon, R., Spindler, X., Maynard, P., Lennard, C. & Roux, C. 2011, 'Investigation of hydrogen cyanide generation from the cyanoacrylate fuming process used for latent fingermark detection', Forensic Science International, vol. 212, no. 1-3, pp. 143-149.
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Cyanoacrylate fuming is one of the most common techniques employed for the detection of latent fingermarks on non-porous surfaces such as plastic and glass. The technique is generally applied by exposing items of interest to the vapours generated by heating a suitable quantity of commercial cyanoacrylate adhesive. In this study, the potential for highly toxic hydrogen cyanide (HCN) to be generated from the overheating of cyanoacrylate was investigated. Two commercial cyanoacrylate adhesives and two quantitative methods for the determination of HCN were employed: (i) the sodium picrate method; and (ii) the picrate-resorcinol method. 13C nuclear magnetic resonance (NMR) analysis was used to confirm the presence of cyanide. In addition, the thermal decomposition of cyanoacrylate was studied using simultaneous thermogravimetric and differential thermal analysis (TGA-DTA). It was determined that detectable and quantifiable amounts of HCN were generated from the thermal decomposition of cyanoacrylate monomer and polymer at temperatures as low as 200C. Using an optimised picrate-resorcinol method, it was shown that around 10?g of HCN could be generated from the heating of 1g of cyanoacrylate monomer at 200C. For one of the adhesives tested, this increased to above 100?g of HCN when 1g of cyanoacrylate monomer was heated at 280C. Recommendations are provided that, if followed, should ensure that the cyanoacrylate fuming process can be safely applied with minimal risk to the operator. 2011 Elsevier Ireland Ltd.
Spindler, X., Hofstetter, O., McDonagh, A.M., Roux, C. & Lennard, C. 2011, 'Enhancement of latent fingermarks on non-porous surfaces using anti-l-amino acid antibodies conjugated to gold nanoparticles', Chemical Communications, vol. 47, no. 19, pp. 5602-5604.
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Enantioselective anti-l-amino acid antibodies conjugated to gold nanoparticles are shown to facilitate the detection of latent fingermarks by interacting with amino acids present in friction ridge secretions. This antibody-based system is particularly effective for the enhancement of aged and dried fingermarks on non-porous surfaces, an area unexploited by current techniques. 2011 The Royal Society of Chemistry.
Chan, J., Shimmon, R., Spindler, X., Maynard, P., Lennard, C., Roux, C. & Stuart, B.H. 2010, 'An investigation of isatin as a potential reagent for latent fingermark detection on porous surfaces', Journal of Forensic Identification, vol. 60, no. 3, pp. 320-336.
This study investigated isatin as a potential fingermark enhancement reagent for use on porous surfaces. A number of parameters were investigated, including concentration, solvent system, pH of the solution, and optimization of the development conditions. It was determined that isatin at a concentration of 0.05% (w/v) provided the optimum balance between the luminescence of the fingermark ridges and background. A carrier solvent of dioxane mixed with acetone [12.5% (v/v)] produced the most intense luminescence. It was determined that the optimum pH for the development of fingermarks was 5.0 and that this could be reached by the addition of 4% (v/v) sodium carbonate buffer. The use of a dry heat press at 180C for 10 s provided optimal development conditions. The possible enhancement of isatin-treated fingermark impressions using metal salts was investigated and it was determined that secondary treatment with an ethanolic zinc chloride solution provided enhanced luminescence emission. However, little color change to the developed fingermarks was observed. A comparison of isatin with 1,2-indanedione-zinc (IND-Zn) and DFO demonstrated that the latter two reagents provided greater sensitivity and luminescence than isatin despite the fact that isatin generated strong room-temperature luminescence.