An electrochemical sensor based on Fe₃O₄@GO@MIP nanoparticles has been proposed for interleukin-8 detection in saliva.

Owing to their potential to transform traditional medical diagnostics and health monitoring, wearable biosensors have become an alternative evolutionary technology in the field of medical care. However, it is still necessary to overcome some key technique challenges, such as the selectivity, sensitivity, and stability of biometric identification. Herein, a novel, wearable electrochemical sensor based on a molecularly imprinted polymer (MIP) integrated with a copper benzene-1,3,5-tricarboxylate metal–organic framework (MOF) was designed for the detection of stress through the on-body monitoring of cortisol in sweat. The MOF was used as the substrate for MIP deposition to enhance the stability and sensitivity of the sensor. The sensor consisted of two layers, with a microfluidic layer as the top layer for spontaneous sweating and a modified electrode as the bottom layer for sensing. The sensor measured cortisol levels by detecting the current change that occurred when the target molecules bound to the imprinted cavities, using Prussian blue nanoparticles embedded in the MIP framework as the REDOX probe. The proposed sensor exhibited a linear detection range of 0.01–1000 nM with a detection limit of 0.0027 nM, and favorable specificity over other analogies. This facile anti-body free sensor showed excellent stability, and can be successfully applied for in situ cortisol monitoring.

Prostate-specific membrane antigen (PSMA) is a biomarker for prostate cancer (PCa), and a specific and reliable detection technique of PSMA is urgently required for PCa early diagnosis. A Love wave sensor has been widely studied for real-time sensing and highly sensitive applications, but the sensing unit needs special handling for selective detection purpose. In this study, we prepared a versatile Love wave sensor functionalized with molecularly-imprinted polymers (MIP), PSMA as the template molecule. To enhance the specific template bindings of MIP in pure aqueous solutions, facile reversible addition/fragmentation chain transfer (RAFT) precipitation polymerization (RAFTPP) was used to produce surface hydrophilic polymer brushes on MIP. The presence of hydrophilic polymer brushes on MIP improved its surface hydrophilicity and significantly reduced their hydrophobic interactions with template molecules in pure aqueous media. In detection process, the acoustic delay-line is confederative to a microfluidic chip and inserted in an oscillation loop. The real-time resonance frequency of the MIP-based Love wave sensor to different concentrations of PSMA was investigated. The limit of detection (LOD) for this Love SAW sensor was 0.013 ng mL⁻¹, which demonstrates that this sensor has outstanding performance in terms of the level of detection.

Protein surface imprinting produces materials capable of selective recognition and capture of proteins. Herein, a protein surface imprinted polymer on graphene oxide modified super-paramagnetic Fe₃O₄ nanoparticles is reported. The molecularly imprinted polymer was synthesized by ultrasound-assisted suspension polymerization, using ovalbumin as the template molecule, 3-aminophenylboronie acid as the functional monomer, and methylene-bis-acrylamide as the cross-linking agent. The nanoparticles were approximately 40 nanometers in size and super-paramagnetic. Moreover, these particles demonstrated considerably high adsorption capacity, fast adsorption kinetics, and selective binding affinities toward the template protein ovalbumin. The calibration curve of ovalbumin was linear from 5.0 × 10⁻¹¹ to 1.0 × 10⁻¹⁰ molar. The limit of detection of ovalbumin was 2.0 × 10⁻¹¹ M. These results show that this super-paramagnetic material has potential for biological macromolecule separation and determination.

Recently, the development of fluorescent probes has contributed to significant advances in cell biology and medical diagnostic imaging. In this work, we use biocompatible bovine hemoglobin (BHb) molecules to co-coat aggregation-induced emission (AIE) molecules amino tetraphenylethylene (TPE-NH ₂ ) and near-infrared emission molecules 2-(4-aminophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl) fumaronitrile (TPAADFN), to get TPE-NH ₂ /TPAADFN@BHb nanoparticles. Due to the fluorescence resonance energy transfer (FRET) between the two fluorescent molecules, the prepared fluorescent nanoparticles have high fluorescence quantum efficiency. The prepared TPE-NH ₂ /TPAADFN@BHb nanoparticles also have large Stokes shift, which helps to avoid the cross-talk between the absorption and emission of the particles themselves. This is beneficial to avoid the self-absorption of biological tissues and obtain very high detection sensitivity. Furthermore, due to the good biocompatibility of BHb, TPE-NH ₂ /TPAADFN@BHb nanoparticles have good mono-dispersity, low toxicity and high brightness, which is very propitious in the application of bio-imaging.