Instrument-free nucleic acid amplification assays for global health settings

Abstract

Many infectious diseases that affect global health are most accurately diagnosed through nucleic acid amplification and detection. However, existing nucleic acid amplification tests are too expensive and complex for most low-resource settings. The small numbers of centralized laboratories that exist in developing countries tend to be in urban areas and primarily cater to the affluent. In contrast, rural area health care facilities commonly have only basic equipment and health workers have limited training and little ability to maintain equipment and handle reagents.1 Reliable electric power is a common infrastructure shortfall. In this paper, we discuss a practical approach to the design and development of non-instrumented molecular diagnostic tests that exploit the benefits of isothermal amplification strategies. We identify modular instrument-free technologies for sample collection, sample preparation, amplification, heating, and detection. By appropriately selecting and integrating these instrument-free modules, we envision development of an easy to use, infrastructure independent diagnostic test that will enable increased use of highly accurate molecular diagnostics at the point of care in low-resource settings.

Disposable DNA Amplification Chips with Integrated Low-Cost Heaters †

“…The work presented at the 4th Microfluidic Handling Systems conference and which is extended in this paper aims at the development of a disposable, polymer-based DNA amplification lab-on-chip system with integrated resistive heater based on the World Health Organization (WHO) Sexually Transmitted Diseases Diagnostics Initiative (SDI) ASSURED criteria. Devices which are ASSURED are (A) affordable, (S) sensitive, (S) specific, (U) user-friendly, (R) robust and rapid, (E) equipment-free, and (D) deliverable to those who need them [20,49]. The first step towards such a device is the development of the chip itself.…”

Single-use, electricity-free amplification device for detection of HIV-1

“…To simplify the overall design of the NAT platform and reduce material costs, alternative sources of heat, coupled to isothermal amplification methods, have been explored for rapid NAT development. One such approach involves harnessing the heat from exothermic chemical reactions (LaBarre et al, 2011; Labarre et al, 2010). Prototype electricity-free, non-instrumented nucleic acid (NINA) heaters have been developed and demonstrated for detection of malaria and HIV (Labarre et al, 2010; Lillis et al, 2014; Sema et al, 2015; Singleton et al, 2014).…”

“…CaO or Mg-Fe) that provide the heat source for amplification. Depending on the optimal temperature for the specific isothermal amplification method, the design of the NINA unit is flexible and has been constructed from an insulated thermos or small soufflé cup (Curtis et al, 2012; LaBarre et al, 2011). …”

Paperfuge: An ultra-low cost, hand-powered centrifuge inspired by the mechanics of a whirligig toy

“…From extraction of plasma from whole blood (for performing immunoassays or determining hematocrit value), to concentration of pathogens and parasites in biological fluids such as blood, urine and stool (for microscopy), centrifugation is the first key-step for most diagnostic assays (1). In modern diagnostics, separation of unwanted cellular debris is especially critical for the accuracy and reliability of molecular diagnostics tools and lateral flow-based rapid diagnostic tests (RDT) (2) that are designed for detecting low-levels of infections in diseases such as malaria, HIV and tuberculosis (3)(4)(5). Currently, centrifugation is inaccessible in field conditions since conventional machines are bulky, expensive and require electricity (4).…”

“…In modern diagnostics, separation of unwanted cellular debris is especially critical for the accuracy and reliability of molecular diagnostics tools and lateral flow-based rapid diagnostic tests (RDT) (2) that are designed for detecting low-levels of infections in diseases such as malaria, HIV and tuberculosis (3)(4)(5). Currently, centrifugation is inaccessible in field conditions since conventional machines are bulky, expensive and require electricity (4). The need for electricity-free centrifugal bio-separation devices prompted researchers to use egg-beaters and salad-spinners as proposed devices (6,7).…”