Group selective aptamers: Broad-spectrum recognition of target groups in Cronobacter species and implementation of electrochemical biosensors as receptors.

Aptamers are a versatile class of receptors with a high affinity and selectivity for specific targets. Although their ability to recognize individual targets has been extensively studied, some scenarios require the development of receptors capable of identifying all target groups. This study investigated the use of aptamers to achieve the broad-spectrum recognition of groups instead of individual targets. Aptamers were screened for selectively distinct groups of Cronobacter species associated with foodborne diseases. Seven Cronobacter spp. were divided into Group A (C. sakazakii, C. malonaticus, C. turicensis, and C. muytjensii) and Group B (C. dublinensis, C. condimenti, and C. universalis). Aptamers with exclusive selectivity for each group were identified, allowing binding to the species within their designated group while excluding those from the other group. The screened aptamers demonstrated reliable affinity and specificity with dissociation constants ranging from 1.3 to 399.7 nM for Group A and 4.0-24.5 nM for Group B. These aptamers have also been successfully employed as receptors in an electrochemical biosensor platform, enabling the selective detection of each group based on the corresponding aptamer (limit of detection was 7.8 and 3.2 CFU for Group A and Group B, respectively). The electrochemical sensor effectively detected the extent of infection in each group in powdered infant formula samples. This study highlights the successful screening and application of group-selective aptamers as sensing receptors, emphasizing their potential for diverse applications in different fields such as food safety, environmental monitoring, and clinical diagnostics, where the selective biosensing of target groups is crucial.

Biosensors for healthcare: current and future perspectives.

Biosensors are utilized in several different fields, including medicine, food, and the environment; in this review, we examine recent developments in biosensors for healthcare. These involve three distinct types of biosensor: biosensors for in vitro diagnosis with blood, saliva, or urine samples; continuous monitoring biosensors (CMBs); and wearable biosensors. Biosensors for in vitro diagnosis have seen a significant expansion recently, with newly reported clustered regularly interspaced short palindromic repeats (CRISPR)/Cas methodologies and improvements to many established integrated biosensor devices, including lateral flow assays (LFAs) and microfluidic/electrochemical paper-based analytical devices (µPADs/ePADs). We conclude with a discussion of two novel groups of biosensors that have drawn great attention recently, continuous monitoring and wearable biosensors, as well as with perspectives on the commercialization and future of biosensors.

Aptamer duo-based portable electrochemical biosensors for early diagnosis of periodontal disease.

Recently, point-of-care tests (POCT) have gained much attention due to their convenient, fast, simple, and easy characteristics. For POCT, portability is an essential feature. In this study, we have successfully fabricated a portable mini-potentiostat. Using chronoamperometry, electrical signals of this portable mini-potentiostat were measured, and the analytical performance of electrochemical aptasensors was compared with a benchtop potentiostat. The electrochemical signals measured by mini-potentiostat can be displayed on the screen of a smartphone. To verify the analytical performance of this portable electrochemical aptasensor platform with a mini-potentiostat, two well-known model protein biomarkers, vaspin, a type 2 diabetes biomarker, and thrombin, a biomarker for pulmonary metastasis and cardiovascular disease, were confirmed to be detected by using corresponding aptamer duo. After solid verification of this portable electrochemical aptasensor platform, we have successfully implemented this portable mini-potentiostat system to develop a portable sandwich-type binding pair of aptamers-based electrochemical biosensor, which can diagnose periodontal disease by measuring ODAM biomarker. The linear range of this ODAM biosensor was 0 to 15 nM with a detection limit of 0.02 nM and 1 nM in buffer and saliva, respectively. The sensitivity of this biosensor has been greatly enhanced, compared to previously developed surface plasmon resonance (SPR) or lateral flow assay (LFA) based aptasensors. This study showed that this new portable aptamer duo-based biosensor is expected to diagnose the early stage of periodontal diseases from real samples, such as saliva or gingival crevicular fluid in a short time as a point-of-care (POC) testing.