Virus is a kind of microorganism and possesses simple structure and contains one nucleic acid, which must be replicated using the host cell system. It causes large-scale infectious diseases and poses serious threats to the health, social well-being, and economic conditions of millions of people worldwide. Therefore, there is an urgent need to develop novel strategies for accurate diagnosis of virus infection to prevent disease transmission. Quantum dots (QDs) are typical fluorescence nanomaterials with high quantum yield, broad absorbance range, narrow and size-dependent emission, and good stability. QDs-based nanotechnology has been found to be effective method with rapid response, easy operation, high sensitivity, and good specificity, and has been widely applied for the detection of different viruses. However, until now, no systematic and critical review has been published on this important research area. Hence, in this review, we aim to provide a comprehensive coverage of various QDs-based virus detection methods. The fundamental investigations have been reviewed, including information related to the synthesis and biofunctionalization of QDs, QDs-based viral nucleic acid detection strategies, and QDs-based immunoassays. The challenges and perspectives regarding the potential application of QDs for virus detection is also discussed.Virus is a kind of microorganism and possesses simple structure and contains one nucleic acid, which must be replicated using the host cell system. It causes large-scale infectious diseases and poses serious threats to the health, social well-being, and economic conditions of millions of people worldwide. Therefore, there is an urgent need to develop novel strategies for accurate diagnosis of virus infection to prevent disease transmission. Quantum dots (QDs) are typical fluorescence nanomaterials with high quantum yield, broad absorbance range, narrow and size-dependent emission, and good stability. QDs-based nanotechnology has been found to be effective method with rapid response, easy operation, high sensitivity, and good specificity, and has been widely applied for the detection of different viruses. However, until now, no systematic and critical review has been published on this important research area. Hence, in this review, we aim to provide a comprehensive coverage of various QDs-based virus detection methods. The fundamental investigations have been reviewed, including information related to the synthesis and biofunctionalization of QDs, QDs-based viral nucleic acid detection strategies, and QDs-based immunoassays. The challenges and perspectives regarding the potential application of QDs for virus detection is also discussed.

Based on natural protein materials, a series of lenses with different heights and focal lengths were assembled on glass substrates by femtosecond laser non-contact, masking, and cold processing. This lens array itself possesses unique and characteristic optical performance in three-dimensional parallel imaging and bending imaging. What is more profound is that by using equilibrium swelling of protein-hydrogel, once the lens array was placed in a liquid environment, with the change of ion concentration (e.g., pH), the refractive index and curvature of the protein-hydrogel would change, which leads to the flex of the focal plane of the lens, finally realizing the dynamical tunability of a protein microlens. These smart stress devices may have great potential in optical biosensing and microfluidic chip integration fields.

The denaturation of double-stranded deoxyribonucleic acid (ds-DNA) has been well known to break nucleobase bonds, resulting in single-stranded deoxyribonucleic acid (ss-DNA) in solutions, which can recombine to form ds-DNA in a reversible manner. We developed an efficient process to irreversibly maintain various DNA denaturation levels in thin solid films in order to investigate the impacts of the denaturation on the optical properties of DNA films. By adding NaOH in an aqueous solution of salmon testis DNA, we flexibly controlled the level of denaturation in the solution, which was then spin-coated on Si and silica substrates to irreversibly bind ss-DNAs in a thin solid film. The denaturation of DNA in thin solid films was experimentally confirmed by ultraviolet-visible and Fourier transform infrared spectroscopic investigations, whose level could be controlled by the NaOH content in the aqueous solution precursor. By this irreversible denaturation process, we developed a new method to flexibly vary the refractive index of DNA thin solid films in a wide range of Δn>0.02 in the visible to near-infrared range. Thermo-optic coefficients dn/dT of the films were also experimentally measured in the temperature range from 40°C to 90°C to confirm the significant impacts of denaturation. Detailed thin film processes and optical characterizations are discussed.

Brain regenerative studies require precise visualization of the morphological structures. However, few imaging methods can effectively detect the adult zebrafish brain in real time with high resolution and good penetration depth. Long-term in vivo monitoring of brain injuries and brain regeneration on adult zebrafish is achieved in this study by using 1325 nm spectral-domain optical coherence tomography (SD-OCT). The SD-OCT is able to noninvasively visualize the skull injury and brain lesion of adult zebrafish. Valuable phenomenon such as the fractured skull, swollen brain tissues, and part of the brain regeneration process can be conducted based on the SD-OCT images at different time points during a period of 43 days.