Qisheng Jiang

Bilayered Biofoam for Highly Efficient Solar Steam Generation.

A novel bilayered hybrid biofoam composed of a bacterial nanocellulose (BNC) layer and a reduced graphene oxide (RGO)-filled BNC layer is introduced for highly efficient solar steam generation. The biofoam exhibits a solar thermal efficiency of ≈83% under simulated solar illumination (10 kW m-2 ). The fabrication method introduced here is highly scalable and cost-efficient.

Wood–Graphene Oxide Composite for Highly Efficient Solar Steam Generation and Desalination

Solar steam generation is a highly promising technology for harvesting solar energy, desalination and water purification. We introduce a novel bilayered structure composed of wood and graphene oxide (GO) for highly efficient solar steam generation. The GO layer deposited on the microporous wood provides broad optical absorption and high photothermal conversion resulting in rapid increase in the temperature at the liquid surface. On the other hand, wood serves as a thermal insulator to confine the photothermal heat to the evaporative surface and to facilitate the efficient transport of water from the bulk to the photothermally active space. Owing to the tailored bilayer structure and the optimal thermo-optical properties of the individual components, the wood-GO composite structure exhibited a solar thermal efficiency of ∼83% under simulated solar excitation at a power density of 12 kW/m2. The novel composite structure demonstrated here is highly scalable and cost-efficient, making it an attractive material for various applications involving large light absorption, photothermal conversion and heat localization.

Plasmonic Biofoam: A Versatile Optically Active Material

Owing to their ability to confine and manipulate light at the nanoscale, plasmonic nanostructures are highly attractive for a broad range of applications. While tremendous progress has been made in the synthesis of size- and shape-controlled plasmonic nanostructures, their integration with other materials and application in solid-state is primarily through their assembly on rigid two-dimensional (2D) substrates, which limits the plasmonically active space to a few nanometers above the substrate. In this work, we demonstrate a simple method to create plasmonically active three-dimensional biofoams by integrating plasmonic nanostructures with highly porous biomaterial aerogels. We demonstrate that plasmonic biofoam is a versatile optically active platform that can be harnessed for numerous applications including (i) ultrasensitive chemical detection using surface-enhanced Raman scattering; (ii) highly efficient energy harvesting and steam generation through plasmonic photothermal heating; and (iii) optical control of enzymatic activity by triggered release of biomolecules encapsulated within the aerogel. Our results demonstrate that 3D plasmonic biofoam exhibits significantly higher sensing, photothermal, and loading efficiency compared to conventional 2D counterparts. The design principles and processing methodology of plasmonic aerogels demonstrated here can be broadly applied in the fabrication of other functional foams.

Polydopamine-filled bacterial nanocellulose as a biodegradable interfacial photothermal evaporator for highly efficient solar steam generation

Solar steam generation by heat localization is considered to be a highly efficient, sustainable way to alleviate water shortage in resource-limited regions. However, most of the interfacial photothermal evaporators demonstrated so far involve non-biodegradable nanoscale materials, which can quickly pose a significant threat to the environment and ecosystems, especially marine ecosystems, after their disposal. For the first time, a flexible, scalable and, more importantly, completely biodegradable photothermal evaporator for highly efficient solar steam generation is introduced. The bilayered evaporator is comprised of bacterial nanocellulose (BNC) densely loaded with polydopamine (PDA) particles during its growth. The biodegradable foam introduced here exhibits large light absorption and photothermal conversion, heat localization, and efficient water transportation, leading to an excellent solar steam generation performance under one sun (efficiency of ∼78%). The novel material and scalable process demonstrated here can be a sustainable solution to alleviate the global water crisis.

An in situ grown bacterial nanocellulose/graphene oxide composite for flexible supercapacitors

Recently, the development of flexible supercapacitors has received significant attention due to their application in flexible electronics such as bendable mobile phones, flexible displays and wearable devices. Owing to numerous advantages such as excellent mechanical strength, low cost, high porosity and natural abundance, bacterial nanocellulose (BNC) is considered to be highly attractive for the fabrication of flexible supercapacitors. This work demonstrates that BNC can serve as an ideal layered matrix for incorporation of active two-dimensional (2D) materials. A novel strategy for the incorporation of graphene oxide (GO) sheets into layered BNC during its growth is presented. GO flakes can be interlocked within the nanocellulose network during BNC growth, enabling facile chemical reduction of GO sheets, which prevents their restacking and loss of active area and leads to excellent energy storage performance as well as mechanical flexibility. Significantly, the fabrication approach demonstrated here can be extended to other 2D nanomaterials to realize flexible BNC-based energy storage devices.

PEGylated Artificial Antibodies: Plasmonic Biosensors with Improved Selectivity.

Molecular imprinting, which involves the formation of artificial recognition elements or cavities with complementary shape and chemical functionality to the target species, is a powerful method to overcome a number of limitations associated with natural antibodies. An important but often overlooked consideration in the design of artificial biorecognition elements based on molecular imprinting is the nonspecific binding of interfering species to noncavity regions of the imprinted polymer. Here, we demonstrate a universal method, namely, PEGylation of the noncavity regions of the imprinted polymer, to minimize the nonspecific binding and significantly enhance the selectivity of the molecular imprinted polymer for the target biomolecules. The nonspecific binding, as quantified by the localized surface plasmon resonance shift of imprinted plasmonic nanorattles upon exposure to common interfering proteins, was found to be more than 10 times lower compared to the non-PEGylated counterparts. The method demonstrated here can be broadly applied to a wide variety of functional monomers employed for molecular imprinting. The significantly higher selectivity of PEGylated molecular imprints takes biosensors based on these artificial biorecognition elements closer to real-world applications.

Influence of Surface Charge of the Nanostructures on the Biocatalytic Activity

The physicochemical properties of abiotic nanostructures determine the structure and function of biological counterparts in biotic-abiotic nanohybrids. A comprehensive understanding of the interfacial interactions and the predictive capability of their structure and function is paramount for virtually all fields of bionanotechnology. In this study, using plasmonic nanostructures as a model abiotic system, we investigate the effect of the surface charge of nanostructures on the biocatalytic reaction kinetics of a bound enzyme. We found that the surface charge of nanostructures profoundly influences the structure, orientation, and activity of the bound enzyme. Furthermore, the interactions of the enzyme with nanoparticles result in stable conjugates that retain their functionality at elevated temperatures, unlike their free counterparts that lose their secondary structure and biocatalytic activity.

Rapid, Point‐of‐Care, Paper‐Based Plasmonic Biosensor for Zika Virus Diagnosis

Zika virus (ZIKV) is an increasing global health challenge. There is an urgent need for rapid, low‐cost, and accurate diagnostic tests that can be broadly distributed and applied in pandemic regions. Here, an innovative, adaptable, and rapidly deployable bioplasmonic paper‐based device (BPD) is demonstrated for the detection of ZIKV infection, via quantification of serum anti‐ZIKV‐nonstructural protein 1 (NS1) IgG and IgM. BPD is based on ZIKV‐NS1 protein as a capture element and gold nanorods as plasmonic nanotransducers. The BPD displays excellent sensitivity and selectivity to both anti‐ZIKV‐NS1 IgG and IgM in human serum. In addition, excellent stability of BPDs at room and even elevated temperature for one month is achieved by metal–organic framework (MOF)‐based biopreservation. MOF‐based preservation obviates the need for device refrigeration during transport and storage, thus enabling their use in point‐of‐care and resource‐limited settings for ZIKV surveillance. Furthermore, the versatile design (interchangeable recognition element) of BPDs more generally enables their ready adaptation to diagnose other emerging infectious diseases.

Catalytically Active Bacterial Nanocellulose-Based Ultrafiltration Membrane

Large quantities of highly toxic organic dyes in industrial wastewater is a persistent challenge in wastewater treatment processes. Here, for highly efficient wastewater treatment, a novel membrane based on bacterial nanocellulose (BNC) loaded with graphene oxide (GO) and palladium (Pd) nanoparticles is demonstrated. This Pd/GO/BNC membrane is realized through the in situ incorporation of GO flakes into BNC matrix during its growth followed by the in situ formation of palladium nanoparticles. The Pd/GO/BNC membrane exhibits highly efficient methylene orange (MO) degradation during filtration (up to 99.3% over a wide range of MO concentrations, pH, and multiple cycles of reuse). Multiple contaminants (a cocktail of 4-nitrophenol, methylene blue, and rhodamine 6G) can also be effectively treated by Pd/GO/BNC membrane simultaneously during filtration. Furthermore, the Pd/GO/BNC membrane demonstrates stable flux (33.1 L m-2 h-1 ) under 58 psi over long duration. The novel and robust membrane demonstrated here is highly scalable and holds a great promise for wastewater treatment.

Add-on plasmonic patch as a universal fluorescence enhancer

Fluorescence-based techniques are the cornerstone of modern biomedical optics, with applications ranging from bioimaging at various scales (organelle to organism) to detection and quantification of a wide variety of biological species of interest. However, the weakness of the fluorescence signal remains a persistent challenge in meeting the ever-increasing demand to image, detect, and quantify biological species with low abundance. Here, we report a simple and universal method based on a flexible and conformal elastomeric film with adsorbed plasmonic nanostructures, which we term a “plasmonic patch,” that provides large (up to 100-fold) and uniform fluorescence enhancement on a variety of surfaces through simple transfer of the plasmonic patch to the surface. We demonstrate the applications of the plasmonic patch in improving the sensitivity and limit of detection (by more than 100 times) of fluorescence-based immunoassays implemented in microtiter plates and in microarray format. The novel fluorescence enhancement approach presented here represents a disease, biomarker, and application agnostic ubiquitously applicable fundamental and enabling technology to immediately improve the sensitivity of existing analytical methodologies in an easy-to-handle and cost-effective manner, without changing the original procedures of the existing techniques.Fluorescence: Stick-on patch fixes weak bio-signalsAdding a stretchy, nanoparticle-embedded elastomer onto standard fluorescence-based immunoassays raises biomarker signal intensities by two orders of magnitude. Nanomaterials such as gold nanorods have strong surface electromagnetic fields that can couple to the emission of a biomolecule’s fluorescent labels and enhance them, but only at certain distances apart. Srikanth Singamaneni, Rajesh Naik, and co-workers at the Washington University in St. Louis, U.S.A. have now put these nanoparticles into thin polydimethylsiloxane sheet to achieve optimal, atom-level contact for plasmonic enhancement on a variety of substrates. Because the patch is attached to immunoassays after analytical steps including antigen capture and fluorescent labeling have occurred, it avoids interfering with well-established technology. As an example, the team showed that biomarkers for kidney injury and disease could be detected at exceptionally low femtogram concentrations in urine samples.