Light-induced self-assembly of bi-color CdTe quantum dots allows the discrimination of multiple proteins

Surface-Engineered Nanomaterials for Optical Array Based Sensing

Array based sensing governed by optical methods provides fast and economic way for detection of wide variety of analytes where the ideality of detection processes depends on the sensor element's versatile mode of interaction with multiple analytes in an unbiased manner. This can be achieved by either the receptor unit having multiple recognition moiety, or their surface property should possess tuning ability upon fabrication called surface engineering. Nanomaterials have a high surface to volume ratio, making them viable candidates for molecule recognition through surface adsorption phenomena, which makes it ideal to meet the above requirements. Most crucially, by engineering a nanomaterial's surface, one may produce cross-reactive responses for a variety of analytes while focusing solely on a single nanomaterial. Depending on the nature of receptor elements, in the last decade the array-based sensing has been considering as multimodal detection platform which operates through various pathway including single channel, multichannel, binding and indicator displacement assay, sequential ON-OFF sensing, enzyme amplified and nanozyme based sensing etc. In this review we will deliver the working principle for Array-based sensing by using various nanomaterials like nanoparticles, nanosheets, nanodots and self-assembled nanomaterials and their surface functionality for suitable molecular recognition.

Multi-mode fluorescence sensing detection based on one core-shell structure quantum dots via different types of mechanisms

Multi-target sensing completed with single chemosensor is cost-effective and pretty attractive for the analysis of multiple analytes in single sample. CdTe/CdS QDs show high fluorescence quantum yield as a probe for the sensing purpose, but only single target is often detected. Here we proposed that three kinds of different response mechanisms were realized using CdTe/CdS QDs with the simultaneous sensing of Fe³⁺, Cr₂O₇^2-, and IO₃^- as model. The specific binding affinity was used to detect Fe³⁺ with the photo-induced electron transfer (PET) mechanism. CdTe/CdS QDs showed intensive fluorescent response to Cr₂O₇^2- owing to the inner filter effect (IFE). IO₃^- is an oxidant and reacts to surface functional groups of CdTe/CdS QDs with oxidation quenching (OQ) mechanism for the selective detection of IO₃^-. The three targets recorded with the three mechanisms were obviously clustered even they were tested at different concentrations. Thus, the targets could be differentiated with each other through their different responses of PET, IFE, and OQ. The linear ranges for the selective detection of Fe³⁺, Cr₂O₇^2-, and IO₃^- were 5.0-100.0, 20.0-140.0 and 1.0-80.0 μM, with the limits of detection as low as 4.1, 9.7, and 0.9 μM, respectively. The proposed methods were satisfactorily applied to accurately detect Fe³⁺, Cr₂O₇^2-, and IO₃^- in real samples and it was further detected iodate and the total amount of iodine in table salt samples. The proposed multi-target detection strategy with the single fluorescence single from single QDs will stimulate the application of the other matrix with abundant response with enhance sensing efficiency.

Array-Based Discriminative Optical Biosensors for Identifying Multiple Proteins in Aqueous Solution and Biofluids

Identification of proteins is an important issue both in medical research and in clinical practice as a large number of proteins are closely related to various diseases. Optical sensor arrays with recognition ability have been flourished to apply for distinguishing multiple chemically or structurally similar analytes and analyzing unknown or mixed samples. This review gives an overview of the recent development of array-based discriminative optical biosensors for recognizing proteins and their applications in real samples. Based on the number of sensor elements and the complexity of constructing array-based discriminative systems, these biosensors can be divided into three categories, which include multi-element-based sensor arrays, environment-sensitive sensor arrays and multi-wavelength-based single sensing systems. For each strategy, the construction of sensing platform and detection mechanism are particularly introduced. Meanwhile, the differences and connections between different strategies were discussed. An understanding of these aspects may help to facilitate the development of novel discriminative biosensors and expand their application prospects.