The skin microbiopsy

Abstract

Skin cancer is reported to incur the highest treatment costs of all cancers. The treatment cost of non-melanoma skin cancer (NMSC) was purported to be around AUD$264 million, and AUD$30 million for melanoma in 2001. Conventional skin biopsy techniques are performed to identify histopathological signs of malignancy. Suspicious lesions are often present on cosmetically sensitive areas and may be present in large numbers, making biopsies unfeasible. As a result, many atypical lesions are left untreated (leaving patients with early cancerous lesions) or needlessly removed (unnecessary scars). Prognostic biomarkers are useful for assessing borderline cases to facilitate early detection of skin cancer. The development of a novel microbiopsy device (Figure 1.1) from this Thesis enables quick, simple, minimally invasive and suture-free sampling of tiny skin samples sufficient for molecular assays.Laser cutting technologies have enabled rapid prototyping of microbiopsy devices made from medical-grade stainless steel. Through optimisation of the laser parameters, a twodimensional microbiopsy that assembles to form a three-dimensional cutting tip with a hallow chamber was successfully constructed. A quick and safe method to facilitate repeated collection over time in human patients is now possible with the microbiopsybased approach.Characterisation studies revealed approximately 1000 to 3000 cells from each velocityaided microbiopsy with an average DNA and RNA yield of 5.9 ± 3.4 ng and 9.0 ± 10.1 ng, respectively. Human volunteer studies have shown that the microbiopsy application ii velocity, channel width, edge surface roughness and geometries were important aspects to achieve reproducible tissue sampling.Genomic profiling of an individual can now be done using microbiopsy sampling approach instead of conventional blood or saliva samples. The limitation of small sample size can be overcome by using high-fidelity amplification technologies for amplifying nucleic acids. The defects left by microbiopsy application observed in histopathological sections were similar to artefacts arising from routine tissue processing. This opens up opportunities for the possibility of in vivo sampling and enables molecular diagnosis without the risk of damaging the lesion -which will help to improve patient care by reducing unnecessary excision. Proof-of-concept studies have established the potential of the guided skin microbiopsy device to study in vivo molecular changes within a targeted area over time, which was impossible in the past.Other than clinical applications, the microbiopsy device also offers a novel approach for live cell assays. Current approaches, in particular those related to the cosmeceutical arena are limited to restrictive regulations on animal testing, and the fact it is often not deemed ethical or practical to use conventional biopsy techniques to assess the effect of cosmetics. One debatable topic in this arena is the likelihood of nanoparticles to infiltrate the viable epidermis and cause cell toxicity. Human...