An accurate, rapid, and cost‐effective biosensor for the quantification of disease biomarkers is vital for the development of early‐diagnostic point‐of‐care systems. The recent discovery of the trans‐cleavage property of CRISPR type V effectors makes CRISPR a potential high‐accuracy bio‐recognition tool. Herein, a CRISPR‐Cas12a (cpf1) based electrochemical biosensor (E‐CRISPR) is reported, which is more cost‐effective and portable than optical‐transduction‐based biosensors. Through optimizing the in vitro trans‐cleavage activity of Cas12a, E‐CRIPSR was used to detect viral nucleic acids, including human papillomavirus 16 (HPV‐16) and parvovirus B19 (PB‐19), with a picomolar sensitivity. An aptamer‐based E‐CRISPR cascade was further designed for the detection of transforming growth factor β1 (TGF‐β1) protein in clinical samples. As demonstrated, E‐CRISPR could enable the development of portable, accurate, and cost‐effective point‐of‐care diagnostic systems.

Manganese dioxides (MnO) are among important environmental oxidants in contaminant removal; however, most existing work has only focused on naturally abundant MnO. We herein report the effects of different phase structures of synthetic MnO on their oxidative activity with regard to contaminant degradation. Bisphenol A (BPA), a frequently detected contaminant in the environment, was used as a probe compound. A total of eight MnO with five different phase structures (α-, β-, γ-, δ-, and λ-MnO) were successfully synthesized with different methods. The oxidative reactivity of MnO, as quantified by pseudo-first-order rate constants of BPA oxidation, followed the order of δ-MnO-1 > δ-MnO-2 > α-MnO-1 > α-MnO-2 ≈ γ-MnO > λ-MnO > β-MnO-2 > β-MnO-1. Extensive characterization was then conducted for MnO crystal structure, morphology, surface area, reduction potential, conductivity, and surface Mn oxidation states and oxygen species. The results showed that the MnO oxidative reactivity correlated highly positively with surface Mn(III) content and negatively with surface Mn average oxidation state but correlated poorly with all other properties. This indicates that surface Mn(III) played an important role in MnO oxidative reactivity. For the same MnO phase structure synthesized by different methods, higher surface area, reduction potential, conductivity, or surface adsorbed oxygen led to higher reactivity, suggesting that these properties play a secondary role in the reactivity. These findings provide general guidance for designing active MnO for cost-effective water and wastewater treatment.

An accurate, rapid, and cost‐effective biosensor for the quantification of disease biomarkers is vital for the development of early‐diagnostic point‐of‐care systems. The recent discovery of the trans‐cleavage property of CRISPR type V effectors makes CRISPR a potential high‐accuracy bio‐recognition tool. Herein, a CRISPR‐Cas12a (cpf1) based electrochemical biosensor (E‐CRISPR) is reported, which is more cost‐effective and portable than optical‐transduction‐based biosensors. Through optimizing the in vitro trans‐cleavage activity of Cas12a, E‐CRIPSR was used to detect viral nucleic acids, including human papillomavirus 16 (HPV‐16) and parvovirus B19 (PB‐19), with a picomolar sensitivity. An aptamer‐based E‐CRISPR cascade was further designed for the detection of transforming growth factor β1 (TGF‐β1) protein in clinical samples. As demonstrated, E‐CRISPR could enable the development of portable, accurate, and cost‐effective point‐of‐care diagnostic systems.

Recent advances in CRISPR based biotechnologies have greatly expanded our capabilities to repurpose CRISPR for the development of biomolecular sensors for diagnosing diseases and understanding cellular pathways. The key attribute that allows CRISPR to be widely utilized is the programmable and highly selective mechanism. In this Minireview, we first illustrate the molecular principle of CRISPR functioning process from sensing to actuating. Next, the CRISPR based biosensing strategies for nucleic acids, proteins and small molecules are summarized. We highlight some of recent advances in applications for in vitro detection of biomolecules and in vivo imaging of cellular networks. Finally, the challenges with, and exciting prospects of, CRISPR based biosensing developments are discussed.