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A Device for the Direct Collection & Transfer of Buccal Samples onto FTA/indicating FTA Elute using a Mixed Matrix System

IP.com Disclosure Number: IPCOM000248026D
Publication Date: 2016-Oct-19
Document File: 4 page(s) / 60K

Publishing Venue

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Abstract

In traditional Forensic workflows using Whatman FTA sample collection cards, biological samples (e.g., buccal cells etc.) are applied to the FTA/FTA elute paper indirectly, by means of a simple device that combines the collection with the transfer of the biological sample in two distinct phases; for example, the EasiCollect device contains a foam head which is used to collect buccal cells from the cheek and transfer them onto the integral FTA paper. FTA/FTA elute paper contains hazardous and toxic chemicals (i.e., SDS and guanidine isothiocyanate respectively), and therefore must not come into direct contact with the skin etc. Therefore biological samples cannot be collected by the direct application from the donor onto the FTA card. Here is described a novel system and method which will enable the direct transfer of biological samples from the donor. This invention consists of an outer sheath of a permeable (or preferably semi-permeable) membrane covering an enclosed Whatman FTA card. This approach is termed a mixed matrix principally because it involves the combination of two different solid membranes into a single integral sample collection device; the outer membrane protects individuals from the hazardous DNA stabilising chemicals associated with the inner membrane. This mixed matrix sample collection device is particularly relevant for the collection of buccal cells during forensic applications. The most outstanding feature of the resulting single step direct collection device is the reduction in the risk of exposure to potentially hazardous chemicals to the end user.

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A Device for the Direct Collection & Transfer of Buccal Samples onto FTA/indicating FTA Elute using a Mixed Matrix System

Introduction

Genetic analysis is a key technology in modern criminal forensics. Among all the associated methods, the collection of buccal cells is the simplest way to capture DNA molecules for subsequent DNA fingerprint analysis. Traditional buccal cell workflows consist of; cellular samples are collected and transferred to chemically-treated Whatman FTA/FTA Elute (GE Healthcare) cellulose-based sample collection cards. These cards are coated with proprietary chemicals that cause cellular lysis, protein denaturation and the prolonged stabilisation of DNA. The liberated DNA becomes associated with the cellulose fibres of the FTA cards. The DNA is subsequently used for forensic analysis via PCR amplification technologies. The direct collection of cellular material on to the FTA cards is prohibitive, due to the toxicity and hazardous nature of the chemicals associated with the FTA cards e.g. detergents and isocyanates. Hence, the transfer must be performed indirectly by using separate collection and transfer steps.

US20100106057A1; Whatman discloses a reliable and cost-effective system for the collection, transfer and subsequent storage of buccal cell DNA: The device is equipped with foam head for cell collection fixed on a plastic stem that can be folded for cell transfer to the FTA paper. The chemically treated FTA paper is fixed and is an integral part of device. Therefore the Easicollect system involves a two step process firstly collection of buccal cells followed by their transfer to the FTA card. The device provides the customer with a method for cell collection and transfer without direct exposure of the oral cavity to the toxic chemicals embedded on the FTA card surface.

As direct cellular collection is not possible using FTA cards, this can lead to a delay in cellular lysis, which may cause compromise the resultant genetic data. The use of non-chemically coated sample collection cards overcomes many of the challenges associated with the use of hazardous chemicals for direct cellular collection but non coated papers are associated with decreased DNA stabilisation and hence are not suitable for the prolonged storage of genetic material.

Summary of the invention

In traditional Forensic workflows using Whatman FTA sample collection cards, biological samples (e.g., buccal cells etc.) are applied to the FTA/FTA elute paper indirectly, by means of a simple device that combines the collection with the transfer of the biological sample in two distinct phases; for example, the EasiCollect device contains a foam head which is used to collect buccal cells from the cheek and transfer them onto the integral FTA paper. FTA/FTA elute paper contains hazardous and toxic chemicals (i.e., SDS and guanidine isothiocyanate respectively), and therefore must not come into direct contact with the skin etc. Therefore bio...