Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles

Virus-inspired strategies for cancer therapy

The intentional use of viruses for cancer therapy dates back over a century. As viruses are inherently immunogenic and naturally optimized delivery vehicles, repurposing viruses for drug delivery, tumor antigen presentation, or selective replication in cancer cells represents a simple and elegant approach to cancer treatment. While early virotherapy was fraught with harsh side effects and low response rates, virus-based therapies have recently seen a resurgence due to newfound abilities to engineer and tune oncolytic viruses, virus-like particles, and virus-mimicking nanoparticles for improved safety and efficacy. However, despite their great potential, very few virus-based therapies have made it through clinical trials. In this review, we present an overview of virus-inspired approaches for cancer therapy, discuss engineering strategies to enhance their mechanisms of action, and highlight their application for overcoming the challenges of traditional cancer therapies.

A Study of the Interface of Gold Nanoparticles Conjugated to Cowpea Fe-Superoxide Dismutase

The iron superoxide dismutase (FeSOD) is a first barrier to defend photosynthetic organisms from superoxide radicals. Although it is broadly present in plants and bacteria, FeSODs are absent in animals. They belong to the same phylogenic family as Mn-containing SODs, which are also highly efficient at detoxifying superoxide radicals. In addition, SODs can react with peroxynitrite, and FeSOD enzyme has already been used to evaluate the anti-nitrative capacity of plant antioxidants. Gold nanoparticles (AuNPs) have been shown to significantly improve the functionality and the efficiency of ligands, providing they are properly assembled. In this work, the characteristics of the recombinant cowpea (Vigna unguiculata) FeSOD (rVuFeSOD) immobilized onto AuNPs were investigated as a function of (1) NP surface chemistry and (2) biofunctionalization methods, either physical adsorption or covalent bonding. The NP surface chemistry was studied by varying the concentration of the ligand molecule 11-mercaptoundecanoic acid (MUA) on the NP surface. The coverage and activity of the protein on AuNPs was determined and correlated to the surface chemistry and the two biofunctionalization methods. rVuFeSOD-AuNPs conjugate stability was monitored through absorption measurements, agarose gel electrophoresis and DLS, enzymatic activity by a colorimetric assay and by in-gel activity assay, and coverage was measured by colorimetric assay. When using physical adsorption, the NP is the most perturbing agent for the activity of the enzyme. In contrast, only the NP coverage was affected by MUA ligand concentration. However, during covalent attachment, both the NP and the concentration of MUA on the surface influenced the enzyme activity, while the coverage of the NP remained constant. The results evidence the importance of the biomolecule and AuNP interaction for the functionality of the hybrid. These strategies can be used to develop electrochemical biosensors for O2•- and for peroxynitrite in biomedical applications.

Inverse design of molecule-metal nanoparticle systems interacting with light for desired photophysical properties

Molecules close to a metal nanoparticle (NP) have significantly different photophysical properties from those of the isolated one. In order to harness the potential of the molecule-NP system, appropriate design guidelines are required. Here, we propose an inverse design method of the optimal molecule-NP systems and incident electric field for desired photophysical properties. It is based on a gradient-based optimization search within the time-dependent quantum chemical description for the molecule and the continuum model for the metal NP. We designed the optimal molecule, relative molecule-NP spatial conformation, and incident electric field of a molecule-NP system to maximize the population transfer to the target electronic state of the molecule. The design results were presented and discussed. The present method is promising as the basis for designing molecule-NP systems and incident fields and accelerates discoveries of efficient molecular plasmonics systems.

Solution properties of spherical gold nanoparticles with grafted DNA chains from simulation and theory

There has been a rapidly growing interest in the use of functionalized Au nanoparticles (NPs) as platforms in multiple applications in medicine and manufacturing. The sensing and targeting characteristics of these NPs, and the realization of precisely organized structures in manufacturing applications using such NPs, depend on the control of their surface functionalization. NP functionalization typically takes the form of polymer grafted layers, and a detailed knowledge of the chemical and structural properties of these layers is required to molecularly engineer the particle characteristics for specific applications. However, the prediction and experimental determination of these properties to enable the rational engineering of these particles is a persistent problem in the development of this class of materials. To address this situation, molecular dynamic simulations were performed based on a previously established coarse-grained single-stranded DNA (ssDNA) model to determine basic solution properties of model ssDNA-grafted NP-layers under a wide range of conditions. In particular, we emphasize the calculation of the hydrodynamic radius for ssDNA-grafted Au NPs as a function of structural parameters such as ssDNA length, NP core size, and surface coverage. We also numerically estimate the radius of gyration and the intrinsic viscosity of these NPs, which in combination with hydrodynamic radius estimates, provide valuable information about the fluctuating structure of the grafted polymer layers. We may then understand the origin of the commonly reported variation in effective NP "size" by different measurement methods, and then exploit this information in connection to material design and characterization in connection with the ever-growing number of applications utilizing polymer-grafted NPs.

Green synthesis of metalloid nanoparticles and its biological applications: A review

Synthesis of metalloid nanoparticles using biological-based fabrication has become an efficient alternative surpassing the existing physical and chemical approaches because there is a need for developing safer, more reliable, cleaner, and more eco-friendly methods for their preparation. Over the last few years, the biosynthesis of metalloid nanoparticles using biological materials has received increased attention due to its pharmaceutical, biomedical, and environmental applications. Biosynthesis using bacterial, fungal, and plant agents has appeared as a faster developing domain in bio-based nanotechnology globally along with other biological entities, thus posing as an option for conventional physical as well as chemical methods. These agents can efficiently produce environment-friendly nanoparticles with the desired composition, morphology (shape as well as size), and stability, along with homogeneity. Besides this, metalloid nanoparticles possess various applications like antibacterial by damaging bacterial cell membranes, anticancer due to damaging tumour sites, targeted drug delivery, drug testing, and diagnostic roles. This review summarizes the various studies associated with the biosynthesis of metalloid particles, namely, tellurium, arsenic, silicon, boron, and antimony, along with their therapeutic, pharmaceutical and environmental applications.

Progress of Nanomaterials-Based Photothermal Therapy for Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the top 15 most prevalent cancers worldwide. However, the current treatment models for OSCC (e.g., surgery, chemotherapy, radiotherapy, and combination therapy) present several limitations: damage to adjacent healthy tissue, possible recurrence, low efficiency, and severe side effects. In this context, nanomaterial-based photothermal therapy (PTT) has attracted extensive research attention. This paper reviews the latest progress in the application of biological nanomaterials for PTT in OSCC. We divide photothermal nanomaterials into four categories (noble metal nanomaterials, carbon-based nanomaterials, metal compounds, and organic nanomaterials) and introduce each category in detail. We also mention in detail the drug delivery systems for PTT of OSCC and briefly summarize the applications of hydrogels, liposomes, and micelles. Finally, we note the challenges faced by the clinical application of PTT nanomaterials and the possibility of further improvement, providing direction for the future research of PTT in OSCC treatment.

Effect of functional anisotropy on the local dynamics of polymer grafted nanoparticles

End-functionalised polymer grafted nanoparticles (PGNs) form bonds when their coronas overlap. The bonded interactions between the overlapping PGNs depend on the energy of the bonds (U). In the present study, oscillatory deformation imposed on a simple system with interacting PGNs placed on the vertices of a triangle is employed to examine the local dynamics as a function of energy of the bonds and the frequency of oscillation relative to the characteristic rupture frequency, ω₀ = 2πν exp(-U/k_BT), of the bonds. In particular, the effect of functional anisotropy is studied by introducing bonds of two different energies between adjacent PGNs. A multicomponent model developed by Kadre and Iyer, Macromol. Theory Simul., 2021, 30, 2100005, that combines the features of effective interactions between PGNs, self-consistent field theory and master equation approach to study bond kinetics is employed to obtain the local dynamics. The resulting force-strain curves are found to exhibit a simple broken symmetry where F_x (γ,) ≠ -F_x (-γ,-) and F_y (γ,) ≠ F_y (-γ,-) in systems with functional anisotropy. Fourier analysis of the dynamic response reveals that functional anisotropy leads to finite even harmonic terms and systematic variation of both the elastic and dissipative response from that of the isotropic systems. Furthermore, the intra-cycle variations in the strain stiffening and shear thickening ratios obtained from the analysis indicate that functional anisotropy leads to anisotropic nonlinear response.

Oxidation of quantum dots encapsulated in block copolymer micelles as a function of polymer terminal charge

Most high-quality quantum dots (QDs) are synthesized in the organic phase, and are often coated with polymers for use in aqueous biological environments. QDs can exhibit fluorescence losses during phase transfer, but evaluating underlying mechanisms (e.g., oxidation, surface etching, loss of colloidal stability) can be challenging because of variation in synthesis methods. Here, fluorescence stability of QDs encapsulated in block co-polymer (BCP) micelles was investigated as a function of BCP terminal functionalization (i.e., -OH, -COOH, and -NH₂ groups) and synthesis method (i.e., electrohydrodynamic emulsification-mediated selfassembly (EE-SA), sonication, and manual shaking). Fluorescence losses, fluorescence intensity, energy spectra, and surface composition were assessed using spectrofluorometry and cathodoluminescence spectroscopy (CL) with integrated X-ray photoemission spectroscopy (XPS). QDs passivated using charged BCPs exhibited 50-80% lower fluorescence intensity than those displaying neutral groups (e.g., -OH), which CL/XPS revealed to result from oxidation of surface Cd to CdO. Fluorescence losses were higher for processes with slow formation speed, but minimized in the presence of poly(vinyl alcohol) (PVA) surfactant. These data suggest slower BCP aggregation kinetics rather than electrostatic chain repulsion facilitated QD oxidation. Thus, polymer coating method and BCP structure influence QD oxidation during phase transfer and should be selected to maximize fast aggregation kinetics.

Ultrasmall Superparamagnetic Iron Oxide Nanoparticles as Nanocarriers for Magnetic Resonance Imaging: Development and In Vivo Characterization

Ultrasmall superparamagnetic iron oxide nanoparticles (uSPIOs) are attractive platforms for the development of smart contrast agents for magnetic resonance imaging (MRI). Oleic acid-capped uSPIOs are commercially available yet hydrophobic, hindering in vivo applications. A hydrophilic ligand with high affinity toward uSPIO surfaces can render uSPIOs water-soluble, biocompatible, and highly stable under physiological conditions. A small overall hydrodynamic diameter ensures optimal pharmacokinetics, tumor delivery profiles, and, of particular interest, enhanced T ₁ MR contrasts. In this study, for the first time, we synthesized a ligand that not only fulfills the as-proposed properties but also provides multiple reactive groups for further modifications. The synthesis delivers a facile approach using commercially available reactants, with resultant uSPIO-ligand constructs assembled through a single-step ligand exchange process. Structural and molecular size analyses confirmed size uniformity and small hydrodynamic diameter of the constructs. On average, 43 reactive amine groups were present per uSPIO nanoparticle. Its r ₁ relaxivity has been tested on a 7 Tesla MR instrument and is comparable to that of the clinically available T ₁ gadolinium-based contrast agent GBCA (1 vs 3 mM^-1 s^-1, respectively). A significant decrease in tumor T1 (15%) within 1 h of injection and complete signal recovery after 2 h were detected with a dose of 7 μg Fe/g mouse. The agent also has high r ₂ relaxivity and can be used for T ₂ contrast-enhanced MRI. Taken together, good relaxation and delivery properties and the presence of multiple surface reactive groups can facilitate its application as a universal MRI-compatible nanocarrier platform.

Chemically Induced Magnetic Dead Shells in Superparamagnetic Ni Nanoparticles Deduced from Polarized Small-Angle Neutron Scattering

Advances in the synthesis and characterization of colloidal magnetic nanoparticles (NPs) have yielded great gains in the understanding of their complex magnetic behavior, with implications for numerous applications. Recent work using Ni NPs as a model soft ferromagnetic system, for example, achieved quantitative understanding of the superparamagnetic blocking temperature-particle diameter relationship. This hinged, however, on the critical assumption of a ferromagnetic NP volume lower than the chemical volume due to a non-ferromagnetic dead shell indirectly deduced from magnetometry. Here, we determine both the chemical and magnetic average internal structures of Ni NP ensembles via unpolarized, half-polarized, and fully polarized small-angle neutron scattering (SANS) measurements and analyses coupled with X-ray diffraction and magnetometry. The postulated nanometric magnetic dead shell is not only detected but conclusively identified as a non-ferromagnetic Ni phosphide derived from the trioctylphosphine commonly used in hot-injection colloidal NP syntheses. The phosphide shell thickness is tunable via synthesis temperature, falling to as little as 0.5 nm at 170 °C. Temperature- and magnetic field-dependent polarized SANS measurements additionally reveal essentially bulk-like ferromagnetism in the Ni core and negligible interparticle magnetic interactions, quantitatively supporting prior modeling of superparamagnetism. These findings advance the understanding of synthesis-structure-property relationships in metallic magnetic NPs, point to a simple potential route to ligand-free stabilization, and highlight the power of the currently available suite of polarized SANS measurement and analysis capabilities for magnetic NP science and technology.

Functional-Group Effect of Ligand Molecules on the Aggregation of Gold Nanoparticles: A Molecular Dynamics Simulation Study

In this paper, atomistic molecular dynamics simulations are performed for the systems consisting of functionalized gold nanoparticles (NPs) in a toluene medium. Gold NPs are coated with ligand molecules that have different terminal groups, that is, polar carboxyl (COOH), hydroxyl (OH), amine (NH₂), and nonpolar methyl (CH₃). These functional groups are selected to understand the relation between the aggregation behavior of functionalized gold NPs in toluene and the polarity of terminal groups of ligand molecules. The center-of-mass distances between NP pairs, the radial distribution functions, the mean square displacements, the radius of gyration, and the number of hydrogen bonds (H-bond) between ligand molecules are computed. Our simulation results indicate that functionalized gold NPs exhibit different aggregation/dispersion behaviors depending upon the terminal group of ligands.

Carboxymethyl Dextran-Based Nanomicelle Coatings on Microarc Oxidized Titanium Surface for Percutaneous Implants: Drug Release, Antibacterial Properties, and Biocompatibility

Bacterial contamination and biofilm formation onpercutaneous implants can lead to device failure and be life-threatening. To solve this issue, we constructed a carboxymethyl dextran- (CMD-) based nanomicelle antibacterial coating on the microarc-oxidized titanium (MAO-Ti) surface (described in the supplementary file). The self-assembled CMD-based nanomicelles and octadecylamine (ODA) were developed as a drug carrier and loaded with minocycline (MC). The characterization and stability of the MC-loaded nanomicelles were determined. The surface roughness, hydrophilicity, and drug release property of the coatings were also investigated. Our findings showed that the cross-linked MC-loaded nanomicelles (MC@(ODA-CMD)CL) were more stable than the uncross-linked nanomicelles. Moreover, MC@(ODA-CMD)CL was successfully incorporated into the pores of MAO-Ti, which significantly increased the surface hydrophilicity of the coatings without influencing their surface roughness. In addition, the coatings demonstrated a sustained release time of 360 h, with a cumulative release rate reaching 86.6%. Staphylococcus aureus (S. aureus) was used to determine the antibacterial properties of the coatings, and human skin fibroblasts were seeded on them to investigate their biocompatibility. The results showed that the coatings significantly reduced the number of adhesive S. aureus and promoted the viability, adhesion, and morphology of the human skin fibroblasts compared to smooth titanium (S-Ti) sheets. In conclusion, MC-loaded CMD-based nanomicelles coated on MAO-Ti surface (MC@(ODA-CMD)CL-Ti) demonstrated sustained-release properties, excellent antibacterial properties and biocompatibility, and promising potential as coatings for percutaneous implants.

Nanomaterials-Mediated Therapeutics and Diagnosis Strategies for Myocardial Infarction

The alarming mortality and morbidity rate of myocardial infarction (MI) is becoming an important impetus in the development of early diagnosis and appropriate therapeutic approaches, which are critical for saving patients' lives and improving post-infarction prognosis. Despite several advances that have been made in the treatment of MI, current strategies are still far from satisfactory. Nanomaterials devote considerable contribution to tackling the drawbacks of conventional therapy of MI by improving the homeostasis in the cardiac microenvironment via targeting, immune modulation, and repairment. This review emphasizes the strategies of nanomaterials-based MI treatment, including cardiac targeting drug delivery, immune-modulation strategy, antioxidants and antiapoptosis strategy, nanomaterials-mediated stem cell therapy, and cardiac tissue engineering. Furthermore, nanomaterials-based diagnosis strategies for MI was presented in term of nanomaterials-based immunoassay and nano-enhanced cardiac imaging. Taken together, although nanomaterials-based strategies for the therapeutics and diagnosis of MI are both promising and challenging, such a strategy still explores the immense potential in the development of the next generation of MI treatment.

Breaking the nanoparticle's dispersible limit via rotatable surface ligands

Achieving versatile dispersion of nanoparticles in a broad range of solvents (e.g., water, oil, and biofluids) without repeatedly recourse to chemical modifications are desirable in optoelectronic devices, self-assembly, sensing, and biomedical fields. However, such a target is limited by the strategies used to decorate nanoparticle's surface properties, leading to a narrow range of solvents for existing nanoparticles. Here we report a concept to break the nanoparticle's dispersible limit via electrochemically anchoring surface ligands capable of sensing the surrounding liquid medium and rotating to adapt to it, immediately forming stable dispersions in a wide range of solvents (polar and nonpolar, biofluids, etc.). Moreover, the smart nanoparticles can be continuously electrodeposited in the electrolyte, overcoming the electrode surface-confined low throughput limitation of conventional electrodeposition methods. The anomalous dispersive property of the smart Ag nanoparticles enables them to resist bacteria secreted species-induced aggregation and the structural similarity of the surface ligands to that of the bacterial membrane assists them to enter the bacteria, leading to high antibacterial activity. The simple but massive fabrication process and the enhanced dispersion properties offer great application opportunities to the smart nanoparticles in diverse fields.

Co-Functionalization of Gold Nanoparticles with C7H2 and HuAL1 Peptides: Enhanced Antimicrobial and Antitumoral Activities

The functionalization of nanoparticles with therapeutic peptides has been pointed out as a promising strategy to improve the applications of these molecules in the field of health sciences. Peptides are highly bioactive but face several limitations such as low bioavailability due to the difficulty of overcoming the physiological barriers in the body and their degradation by enzymes. In this work, gold nanoparticles (AuNPs) were co-functionalized with two therapeutic peptides simultaneously. The peptides from the complementary determining region of monoclonal antibodies, composed of the amino acid sequences YISCYNGATSYNQKFK (C7H2) and RASQSVSSYLA (HuAL1) were chosen for having exhibited antitumor and antimicrobial activity before. The peptides-conjugated AuNPs were characterized regarding size, morphology, and metal concentration by using TEM, dynamic light scattering, and ICP-OES techniques. Then, peptides-conjugated AuNPs were evaluated regarding the antimicrobial activity against E. coli, P. aeruginosa, and C. albicans. The antitumoral activity was evaluated in vitro by cell viability assays with metastatic melanoma cell line (B16F10-Nex2) and the cytotoxicity was evaluated against human foreskin fibroblast (Hs68) cell line. Finally, in vivo assays were performed by using a syngeneic animal model of metastatic melanoma. Our findings have highlighted the potential application of the dual-peptide AuNPs in order to enhance the antitumor and antimicrobial activity of peptides.

Tracing New Landscapes in the Arena of Nanoparticle-Based Cancer Immunotherapy

Over the past two decades, unique and comprehensive cancer treatment has ushered new hope in the holistic management of the disease. Cancer immunotherapy, which harnesses the immune system of the patient to attack the cancer cells in a targeted manner, scores over others by being less debilitating compared to the existing treatment strategies. Significant advancements in the knowledge of immune surveillance in the last few decades have led to the development of several types of immune therapy like monoclonal antibodies, cancer vaccines, immune checkpoint inhibitors, T-cell transfer therapy or adoptive cell therapy (ACT) and immune system modulators. Intensive research has established cancer immunotherapy to be a safe and effective method for improving survival and the quality of a patient’s life. However, numerous issues with respect to site-specific delivery, resistance to immunotherapy, and escape of cancer cells from immune responses, need to be addressed for expanding and utilizing this therapy as a regular mode in the clinical treatment. Development in the field of nanotechnology has augmented the therapeutic efficiency of treatment modalities of immunotherapy. Nanocarriers could be used as vehicles because of their advantages such as increased surface areas, targeted delivery, controlled surface and release chemistry, enhanced permeation and retention effect, etc. They could enhance the function of immune cells by incorporating immunomodulatory agents that influence the tumor microenvironment, thus enabling antitumor immunity. Robust validation of the combined effect of nanotechnology and immunotherapy techniques in the clinics has paved the way for a better treatment option for cancer than the already existing procedures such as chemotherapy and radiotherapy. In this review, we discuss the current applications of nanoparticles in the development of ‘smart’ cancer immunotherapeutic agents like ACT, cancer vaccines, monoclonal antibodies, their site-specific delivery, and modulation of other endogenous immune cells. We also highlight the immense possibilities of using nanotechnology to accomplish leveraging the coordinated and adaptive immune system of a patient to tackle the complexity of treating unique disease conditions and provide future prospects in the field of cancer immunotherapy.

Iron oxide nanoflowers encapsulated in thermosensitive fluorescent liposomes for hyperthermia treatment of lung adenocarcinoma

Magnetic hyperthermia (MHT) is in the spotlight of nanomedical research for the treatment of cancer employing magnetic iron oxide nanoparticles and their intrinsic capability for heat dissipation under an alternating magnetic field (AMF). Herein we focus on the synthesis of iron oxide nanoflowers (Nfs) of different sizes (15 and 35 nm) and coatings (bare, citrate, and Rhodamine B) while comparing their physicochemical and magnetothermal properties. We encapsulated colloidally stable citrate coated Nfs, of both sizes, in thermosensitive liposomes via extrusion, and RhB was loaded in the lipid bilayer. All formulations proved hemocompatible and cytocompatible. We found that 35 nm Nfs, at lower concentrations than 15 nm Nfs, served better as nanoheaters for magnetic hyperthermia applications. In vitro, magnetic hyperthermia results showed promising therapeutic and imaging potential for RhB loaded magnetoliposomes containing 35 nm Nfs against LLC and CULA cell lines of lung adenocarcinoma.

One-step synthesis of gold nanoparticles for catalysis and SERS applications using selectively dicarboxylated cellulose and hyaluronate

Properties and applications of gold nanoparticles (AuNPs) depend on their characteristics which are intrinsically connected to the reducing and capping agents used in their synthesis. Although polysaccharides are commonly used for Au salt reduction, the control over the result is often limited. Here, the selectively dicarboxylated cellulose (DCC) and hyaluronate (DCH) with adjustable composition and molecular weight are used for the first time as reducing and capping agents for AuNPs preparation in an environmental friendly one-step synthesis. Mechanism of reduction and structure-function relationships between the composition of oxidized polysaccharides and properties of formed AuNPs are elucidated and the variances in the macromolecular architecture of dicarboxypolysaccharides are applied to guide the growth of AuNPs. While the homogenous structure and high density of carboxyl groups of fully-oxidized DCC induced isotropic growth of small and uniform AuNPs with good catalytic performance (d = ~20 nm, TOF = 7.3 min^-1, k = 1.47 min^-1), the lower stabilizing potential and slower reduction rates of the DCH induced the anisotropic growth of larger polyhedral ~50 nm nanoparticles, which increased the Surface-Enhanced Raman Scattering efficacy (9× stronger Raman signals on average compared to AuDCC). The use of dicarboxypolysaccharides with adjustable composition and properties thus introduced a new degree of freedom for the preparation of AuNPs with desired properties.

Synergistic Entry of Individual Nanoparticles into Mammalian Cells Driven by Free Energy Decline and Regulated by Their Sizes

Cell entry is one of the common prerequisites for nanomaterial applications. Despite extensive studies on a homogeneous group of nanoparticles (NPs), fewer studies have been performed when two or more types of NPs were coadministrated. We previously described a synergistic cell entry process for two heterogeneous groups of NPs, where NPs functionalized with TAT (transactivator of transcription) peptide (T-NPs) stimulate the cellular uptake of coadministered unfunctionalized NPs (bystander NPs, B-NPs). Here, we show that the synergistic cell entry of NPs is driven by free energy decline and depends on B-NP sizes. Simulations showed that when separately placed initially, two NPs first move toward each other instead of initiating cell entry individually. Only T-NP invokes an inward bending of membrane mimicking endocytosis, which attracts the nearby NPs into the same "vesicle". A two-phase free energy decline of the entire system occurred as two NPs get closer until contact, which is likely the thermodynamic driver for synergistic NP coentry. Experimentally, we found that T-NPs increase the apparent affinity of B-NPs to plasma membrane, suggesting that T-NPs help B-NPs "trapped" in the endocytic vesicles. Next, we varied the sizes of B-NPs and found that bystander activity peaks around 50 nm. Simulations also showed that the size of B-NPs influences the free energy decline, and thus the tendency and dynamics of NP coentry. These efforts provide a system to further understand the synergistic cell entry among individual NPs or multiple NP types on a biophysical basis and shed light on the future design of nanostructures for intracellular delivery.

Three Millennia of Nanocrystals

The broad deployment of nanotechnology and nanomaterials in modern society is increasing day by day to the point that some have seen in this process the transition from the Silicon Age to a new Nano Age. Nanocrystals─a distinct class of nanomaterials─are forecast to play a pivotal role in the next generation of devices such as liquid crystal displays, light-emitting diodes, lasers, and luminescent solar concentrators. However, it is not to be forgotten that this cutting-edge technology is rooted in empirical knowledge and craftsmanship developed over the millennia. This review aims to span the major applications in which nanocrystals were consistently employed by our forebears. Through an analysis of these examples, we show that the modern-age discoveries stem from multimillennial experience passed on from our proto-chemist ancestors to us.

Biorecognition Layer Based On Biotin-Containing [1]Benzothieno[3,2-b][1]benzothiophene Derivative for Biosensing by Electrolyte-Gated Organic Field-Effect Transistors

Requirements of speed and simplicity in testing stimulate the development of modern biosensors. Electrolyte-gated organic field-effect transistors (EGOFETs) are a promising platform for ultrasensitive, fast, and reliable detection of biological molecules for low-cost, point-of-care bioelectronic sensing. Biosensitivity of the EGOFET devices can be achieved by modification with receptors of one of the electronic active interfaces of the transistor gate or organic semiconductor surface. Functionalization of the latter gives the advantage in the creation of a planar architecture and compact devices for lab-on-chip design. Herein, we propose a universal, fast, and simple technique based on doctor blading and Langmuir-Schaefer methods for functionalization of the semiconducting surface of C₈-BTBT-C₈, allowing the fabrication of a large-scale biorecognition layer based on the novel functional derivative of BTBT-containing biotin fragments as a foundation for further biomodification. The fabricated devices are very efficient and operate stably in phosphate-buffered saline solution with high reproducibility of electrical properties in the EGOFET regime. The development of biorecognition properties of the proposed biolayer is based on the streptavidin-biotin interactions between the consecutive layers and can be used for a wide variety of receptors. As a proof-of-concept, we demonstrate the specific response of the BTBT-based biorecognition layer in EGOFETs to influenza A virus (H7N1 strain). The elaborated approach to biorecognition layer formation is appropriate but not limited to aptamer-based receptor molecules and can be further applied for fabricating several biosensors for various analytes on one substrate and paves the way for "electronic tongue" creation.

Optical Properties of Mn-Doped CuGa(In)S-ZnS Nanocrystals (NCs): Effects of Host NC and Mn Concentration

Time-gated fluorescence measurement (TGFM) using long-life fluorescence probes is a highly sensitive fluorescence-measurement technology due to the inherently high signal-to-background ratio. Although many probes for TGFM such as luminescent-metal-complex probes and lanthanide-doped nanoparticles are in development, they generally need sophisticated/expensive instruments for biosensing/imaging applications. Probes possessing high brightness, low-energy (visible light) excitation, and long lifetimes up to milliseconds of luminescence, are highly desired in order to simplify the optical and electronic design of time-gated instruments (e.g., adopting non-UV-grade optics or low-speed electronics), lower the instrument complexity and cost, and facilitate broader applications of TGFM. In this work, we developed Mn-doped CuGa(In)S-ZnS nanocrystals (NCs) using simple and standard synthetic steps to achieve all the desired optical features in order to investigate how the optical properties (fluorescence/absorption spectra, brightness, and lifetimes) of the Mn-doped NCs are affected by different host NCs and Mn concentrations in host NCs. With optimal synthetic conditions, a library of Mn-doped NCs was achieved that possessed high brightness (up to 47% quantum yield), low-energy excitation (by 405 nm visible light), and long lifetimes (up to 3.67 ms). Additionally, the time-domain fluorescence characteristics of optimal Mn-doped NCs were measured under pulsed 405 nm laser excitation and bandpass-filter-based emission collection. The measurement results indicate the feasibility of these optimal Mn-doped NCs in TGFM-based biosensing/imaging.

PLGA-Gold Nanocomposite: Preparation and Biomedical Applications

A composite system consisting of both organic and inorganic nanoparticles is an approach to prepare a new material exhibiting “the best of both worlds”. In this review, we highlight the recent advances in the preparation and applications of poly(lactic-co-glycolic acid)-gold nanoparticles (PLGA-GNP). With its current clinically use, PLGA-based nanocarriers have promising pharmaceutical applications and can “extract and utilize” the fascinating optical and photothermal properties of encapsulated GNP. The resulting “golden polymeric nanocarrier” can be tracked, analyzed, and visualized using the encapsulated gold nanoprobes which facilitate a better understanding of the hosting nanocarrier’s pharmacokinetics and biological fate. In addition, the “golden polymeric nanocarrier” can reveal superior nanotherapeutics that combine both the photothermal effect of the encapsulated gold nanoparticles and co-loaded chemotherapeutics. To help stimulate more research on the development of nanomaterials with hybrid and exceptional properties, functionalities, and applications, this review provides recent examples with a focus on the available chemistries and the rationale behind encapsulating GNP into PLGA nanocarriers that has the potential to be translated into innovative, clinically applicable nanomedicine.

Dynamic nanosurface reconfiguration by host-guest supramolecular interactions

The dynamic functionalization of the nanoparticle surface with biocompatible coatings is a critical step towards the development of functional nano-sized systems. While covalent approaches have been broadly exploited in the stabilization of nanoparticle colloidal systems, these strategies hinder the dynamic nanosurface chemical reconfiguration. Supramolecular strategies based on specific host-guest interactions hold promise due to their intrinsic reversibility, self-healing capabilities and modularity. Host/guest couples have recently been implemented in nanoparticle platforms for the exchange and release of effector molecules. However, the direct exchange of biocompatible hydrophilic oligomers (e.g. peptides) for the modulation of the surface charge and chemical properties of nanoparticles still remains a challenge. Here, we show the intracellular reconfiguration of nanoparticles by a host/guest mechanism with biocompatible oligomeric competitors. The surface of gold nanoparticles was functionalized with cyclodextrin hosts and the guest exchange was studied with biocompatible mono and divalent adamantyl competitors. The systematic characterization of the size and surface potential of the host/guest nanoparticles allowed the optimization of the binding and the stabilization properties of these supramolecular systems. The in cellulo host/guest-mediated direct reconfiguration of the peptide layer at the surface of nanoparticles is achieved by controlling the valence of adamantane-equipped peptides. This work demonstrates that host/guest supramolecular systems can be exploited for the direct exchange of pendants at the surface of nanoparticles and the intracellular dynamic chemical reconfiguration of biocompatible colloidal systems.

Gold nanostructures: synthesis, properties, and neurological applications

Recent advances in technology are expected to increase our current understanding of neuroscience. Nanotechnology and nanomaterials can alter and control neural functionality in both in vitro and in vivo experimental setups. The intersection between neuroscience and nanoscience may generate long-term neural interfaces adapted at the molecular level. Owing to their intrinsic physicochemical characteristics, gold nanostructures (GNSs) have received much attention in neuroscience, especially for combined diagnostic and therapeutic (theragnostic) purposes. GNSs have been successfully employed to stimulate and monitor neurophysiological signals. Hence, GNSs could provide a promising solution for the regeneration and recovery of neural tissue, novel neuroprotective strategies, and integrated implantable materials. This review covers the broad range of neurological applications of GNS-based materials to improve clinical diagnosis and therapy. Sub-topics include neurotoxicity, targeted delivery of therapeutics to the central nervous system (CNS), neurochemical sensing, neuromodulation, neuroimaging, neurotherapy, tissue engineering, and neural regeneration. It focuses on core concepts of GNSs in neurology, to circumvent the limitations and significant obstacles of innovative approaches in neurobiology and neurochemistry, including theragnostics. We will discuss recent advances in the use of GNSs to overcome current bottlenecks and tackle technical and conceptual challenges.

Organic β-cyclodextrin Nanoparticle: An Efficient Building Block Between Functionalized Poly(pyrrole) Electrodes and Enzymes

Glyconanoparticles (GNPs) made by self-assembly of carbohydrate-based polystyrene-block-β-cyclodextrin copolymer are used as a building block for the design of nanostructured biomaterials of electrode. The firm immobilization of GNPs is carried out on electrochemically generated polymer, poly(pyrrole-adamantane), and copolymer, poly(pyrrole-adamantane)/poly(pyrrole-lactobionamide) via host-guest interactions between adamantane and β-cyclodextrin. The ability of GNPs for the specific anchoring of biological macromolecules is investigated using glucose oxidase enzyme modified by adamantane groups as a protein model (GOx-Ad). The immobilization of GOx-Ad is carried out by incubation of an aqueous enzyme solution on a coating of GNPs adsorbed on a platinum electrode. The presence of immobilized GOx-Ad is evaluated in aqueous glucose solution by potentiostating the underlying platinum electrode at 0.7 V/SCE for the electro-oxidation of H₂ O₂ generated by the enzyme. The analytical performance of the bioelectrodes for the detection of glucose is compared to control electrodes prepared without GNPs or without electropolymerized films. The better permeability of copolymer compared to polymer and the possibility to elaborate two alternating layers of GNPs and GOx-Ad are clearly observed. The best amperometric response is recorded with a multilayered bioelectrode displaying a wide linear range linear range of the calibration curve: 68 µmol L^-1 to 0.1 mol L^-1 .

Laser-Ablative Synthesis of Ultrapure Magneto-Plasmonic Core-Satellite Nanocomposites for Biomedical Applications

The combination of magnetic and plasmonic properties at the nanoscale promises the development of novel synergetic image-guided therapy strategies for the treatment of cancer and other diseases, but the fabrication of non-contaminated magneto-plasmonic nanocomposites suitable for biological applications is difficult within traditional chemical methods. Here, we describe a methodology based on laser ablation from Fe target in the presence of preliminarily ablated water-dispersed Au nanoparticles (NPs) to synthesize ultrapure bare (ligand-free) core-satellite nanostructures, consisting of large (several tens of nm) Fe-based core decorated by small (mean size 7.5 nm) Au NPs. The presence of the Fe-based core conditions a relatively strong magnetic response of the nanostructures (magnetization of >12.6 emu/g), while the Au NPs-based satellite shell provides a broad extinction peak centered at 550 nm with a long tale in the near-infrared to overlap with the region of relative tissue transparency (650-950 nm). We also discuss possible mechanisms responsible for the formation of the magnetic-plasmonic nanocomposites. We finally demonstrate a protocol to enhance colloidal stability of the core-satellites in biological environment by their coating with different polymers. Exempt of toxic impurities and combining strong magnetic and plasmonic responses, the formed core-satellite nanocomposites can be used in biomedical applications, including photo- and magneto-induced therapies, magnetic resonance imaging or photoacoustic imaging.

Introducing a Novel Chemotherapeutic Drug for the Treatment of Lung Adenocarcinoma: Silver Nanoparticles Green-formulated by Cinnamomum verum

In this study we report the green synthesis of nontoxic, stable, and small size silver nanoparticle by Cinnamomum verum with reducing/capping ability without any toxic reducing agents. The in situ prepared AgNPs were characterized by advanced physicochemical techniques like FE-SEM, TEM, and UV-Vis study. It has been established that AgNPs have a spherical shape with a mean diameter from 10 to 45 nm. In the antioxidant test, the IC50 of AgNPs and BHT against DPPH free radicals were 191 and 242 µg/mL, respectively. In the cellular and molecular part of the recent study, the treated cells with AgNPs were assessed by MTT assay for 48 h about the cytotoxicity and anti-human lung adenocarcinoma properties on normal (HUVEC) and lung adenocarcinoma cell lines i.e. PC-14, LC-2/ad, and HLC-1. The IC50 of AgNPs were 259, 291, and 395 µg/mL against PC-14, LC-2/ad, and HLC-1 cell lines, respectively. The viability of malignant lung cell line reduced dose-dependently in the presence of AgNPs.

Functionalized Concave Cube Gold Nanoparticles as Potent Antimicrobial Agents against Pathogenic Bacteria

Gold (Au) is an inert metal in a bulk state; however, it can be used for the preparation of Au nanoparticles (i.e., AuNPs) for multidimensional applications in the field of nanomedicine and nanobiotechnology. Herein, monodisperse concave cube AuNPs (CCAuNPs) were synthesized and functionalized with a natural antioxidant lipoic acid (LA) and a tripeptide glutathione (GSH) because different crystal facets of AuNPs provide binding sites for distinct ligands. There was an ∼10 nm bathochromic shift of the UV-vis spectrum when CCAuNPs were functionalized with LA, and the size of the as-synthesized monodisperse CCAu nanoparticles was 76 nm. The LA-functionalized CCAu nanoparticles (i.e., CCAuLA) showed the highest antibacterial activity against Bacillus subtilis. Both fluorescence images and scanning electron microscopy images confirm the damage of the bacterial cell wall as the mode of antibacterial activity of CCAuNPs. CCAuNPs also cause the oxidation of bacterial cell membrane fatty acids to produce reactive oxygen species, which pave the way for the death of bacteria. Both CCAu nanoparticles and their functionalized derivatives showed excellent hemocompatibility (i.e., percentage of hemolysis is <5% at 80 μg of AuNPs) to human red blood cells and very high biocompatibility to HeLa, L929, and Chinese hamster ovary-green fluorescent protein (CHO-GFP) cells. Taken together, LA and GSH enhance the antibacterial activity and biocompatibility, respectively, of CCAu nanoparticles that interact with the bacteria through Coulomb as well as hydrophobic interactions before demonstrating antibacterial propensity.

Medicinal Cannabis Pharmacokinetics and Potential Methods of Delivery

The evidence of cannabis exhibiting polypharmacological properties has been accumulating for the past few decades, particularly for its analgesic and anti-inflammatory abilities. However, inconsistent dosage forms and erratic absorption levels prevent medicinal cannabis products from becoming mainstream recommendations for pain management. Current cannabis products fail to address the undesirable characteristics associated with cannabinoids such as low solubility, poor bioavailability, and lack of specificity, all of which contribute to low therapeutic effect. In this narrative view, the pharmacokinetics of cannabis products and possible methods of drug delivery, in the form of carrier systems, will be explored. The incorporation of cannabinoids into carrier systems provides an opportunity to improve absorption levels, increase bioavailability and reduce adverse events allowing for a greater therapeutic effect.

PEGylation of silver nanoparticles by physisorption of cyclic poly(ethylene glycol) for enhanced dispersion stability, antimicrobial activity, and cytotoxicity

Silver nanoparticles (AgNPs) are practically valuable in biological applications. However, no steady PEGylation has been established, which is essential for internal use in humans or animals. In this study, cyclic PEG (c-PEG) without any chemical inhomogeneity is physisorbed onto AgNPs to successfully PEGylate and drastically enhance the dispersion stability against physiological conditions, white light, and high temperature. In contrast, linear HO-PEG-OH and MeO-PEG-OMe do not confer stability to AgNPs, and HS-PEG-OMe, which is often used for gold nanoparticles, sulfidates the surface to considerably degrade the properties. TEM shows an essentially intact nanostructure of c-PEG-physisorbed AgNPs even after heating at 95 °C, while complete disturbance is observed for other AgNPs. Molecular weight- and concentration-dependent stabilization by c-PEG is investigated, and DLS and ζ-potential measurements prove the formation of a c-PEG layer on the surface of AgNPs. Furthermore, c-PEG-physisorbed AgNPs exhibit persistent antimicrobial activity and cytotoxicity.

Graphene quantum dots-porphyrins/phthalocyanines multifunctional hybrid systems: from interfacial dialogue to applications

Engineered well-ordered hybrid nanomaterials are at a symbolically pivotal point, just ahead of a long-anticipated human race transformation. Incorporating newer carbon nanomaterials like graphene quantum dots (GQDs) with tetrapyrrolic porphyrins...

Thiolated Nanoparticles for Biomedical Applications: Mimicking the Workhorses of Our Body

Advances in nanotechnology have generated a broad range of nanoparticles (NPs) for numerous biomedical applications. Among the various properties of NPs are functionalities being related to thiol substructures. Numerous biological processes that are mediated by cysteine or cystine subunits of proteins representing the workhorses of the bodies can be transferred to NPs. This review focuses on the interface between thiol chemistry and NPs. Pros and cons of different techniques for thiolation of NPs are discussed. Furthermore, the various functionalities gained by thiolation are highlighted. These include overall bio- and mucoadhesive, cellular uptake enhancing, and permeation enhancing properties. Drugs being either covalently attached to thiolated NPs via disulfide bonds or being entrapped in thiolated polymeric NPs that are stabilized via inter- and intrachain crosslinking can be released at the diseased tissue or in target cells under reducing conditions. Moreover, drugs, targeting ligands, biological analytes, and enzymes bearing thiol substructures can be immobilized on noble metal NPs and quantum dots for therapeutic, theranostic, diagnostic, biosensing, and analytical reasons. Within this review a concise summary and analysis of the current knowledge, future directions, and potential clinical use of thiolated NPs are provided.

Click functionalized biocompatible gadolinium oxide core-shell nanocarriers for imaging of breast cancer cells

Site-specific delivery using functionalized nanocarriers is in high demand in imaging applications of modern clinical research. To improve the imaging capabilities of conventionally used contrast agents and expand the targeting accuracy, functional gadolinium oxide based nanocarriers originated from homogeneous core shells structures (Gd₂O₃@SiO₂@Fe₃O₄) were developed using a multilayer formation approach. The synthesis and chemical configuration for the covalent binding of macrocyclic chelating agents and estrogen targeting molecules on these nanocarriers were designed by a two-step chemical synthesis method. Initially, SiO₂@Fe₃O₄ structures were prepared and encapsulated with a homogenous thin Gd₂O₃ overlayer. The exterior surface of the as-prepared carriers offered chemical binding with a breast cancer specific estrogen molecule, covalently grafted through a Click-Chemistry protocol. In the next step, to enhance the diagnostic imaging capabilities of these carriers, thiocyanate-linked chelator molecule, DOTA, was attached to the surface of estrogen bound Gd₂O₃@SiO₂@Fe₃O₄ using basic reaction conditions. The active amino groups before and after conjugation of estrogen molecules on the surface were quantified using a fluorescamine based approach. Due to the covalent binding of the macrocyclic chelator to the Gd₂O₃@SiO₂@Fe₃O₄ surface, core shell carriers showed potential radiolabeling efficiency using positron emitter radionuclide, gallium-68 (⁶⁸Ga). Intracellular uptake of estrogen-conjugated carriers was evaluated with MCF7 breast cancer cell lines using confocal laser scanning microscopy and fluorescent flow cytometry. In addition, in vitro cytotoxicity studies of functional nanocarriers as compared to bare nanoparticles showed reduced toxicity to HEK-293 cells demonstrating the role of surface attached molecules in preventing direct exposure of the Gd₂O₃ surface to the cells. The as-developed gadolinium based nanocarriers presented excellent capabilities as biocompatible target-specific imaging probes which indicates great potential in the field of dual-mode contrast agents.

Site-specific delivery using functionalized nanocarriers is in high demand in imaging applications of modern clinical research.

Photodynamic inactivation (PDI) as a promising alternative to current pharmaceuticals for the treatment of resistant microorganisms

Although the whole world is currently observing the global battle against COVID-19, it should not be underestimated that in the next 30 years, approximately 10 million people per year could be exposed to infections caused by multi-drug resistant bacteria. As new antibiotics come under pressure from unpredictable resistance patterns and relegation to last-line therapy, immediate action is needed to establish a radically different approach to countering resistant microorganisms. Among the most widely explored alternative methods for combating bacterial infections are metal complexes and nanoparticles, often in combination with light, but strategies using monoclonal antibodies and bacteriophages are increasingly gaining acceptance. Photodynamic inactivation (PDI) uses light and a dye termed a photosensitizer (PS) in the presence of oxygen to generate reactive oxygen species (ROS) in the field of illumination that eventually kill microorganisms. Over the past few years, hundreds of photomaterials have been investigated, seeking ideal strategies based either on single molecules (e.g., tetrapyrroles, metal complexes) or in combination with various delivery systems. The present work describes some of the most recent advances of PDI, focusing on the design of suitable photosensitizers, their formulations, and their potential to inactivate bacteria, viruses, and fungi. Particular attention is focused on the compounds and materials developed in our laboratories that are capable of killing in the exponential growth phase (up to seven logarithmic units) of bacteria without loss of efficacy or resistance, while being completely safe for human cells. Prospectively, PDI using these photomaterials could potentially cure infected wounds and oral infections caused by various multidrug-resistant bacteria. It is also possible to treat the surfaces of medical equipment with the materials described, in order to disinfect them with light, and reduce the risk of nosocomial infections.

Continuous Three-Dimensional Printing of Architected Piezoelectric Sensors in Minutes

Additive manufacturing (AM), also known as three-dimensional (3D) printing, is thriving as an effective and robust method in fabricating architected piezoelectric structures, yet most of the commonly adopted printing techniques often face the inherent speed-accuracy trade-off, limiting their speed in manufacturing sophisticated parts containing micro-/nanoscale features. Herein, stabilized, photo-curable resins comprising chemically functionalized piezoelectric nanoparticles (PiezoNPs) were formulated, from which microscale architected 3D piezoelectric structures were printed continuously via micro continuous liquid interface production (μCLIP) at speeds of up to ~60 μm s^-1, which are more than 10 times faster than the previously reported stereolithography-based works. The 3D-printed functionalized barium titanate (f-BTO) composites reveal a bulk piezoelectric charge constant d ₃₃ of 27.70 pC N^-1 with the 30 wt% f-BTO. Moreover, rationally designed lattice structures that manifested enhanced, tailorable piezoelectric sensing performance as well as mechanical flexibility were tested and explored in diverse flexible and wearable self-powered sensing applications, e.g., motion recognition and respiratory monitoring.

Post-synthetic modification of Prussian blue type nanoparticles: tailoring the chemical and physical properties

This review focuses on recent advances in the post-synthetic modification of nano-sized Prussian blue and its analogues and compares them with the current strategies used in metal–organic frameworks to give future outlooks in this field.

Quantitative Surface-Enhanced Spectroscopy

Surface-enhanced Raman scattering (SERS), a powerful technique for trace molecular detection, depends on chemical and electromagnetic enhancements. While recent advances in instrumentation and substrate design have expanded the utility, reproducibility, and quantitative capabilities of SERS, some challenges persist. In this review, advances in quantitative SERS detection are discussed as they relate to intermolecular interactions, surface selection rules, and target molecule solubility and accessibility. After a brief introduction to Raman scattering and SERS, impacts of surface selection rules and enhancement mechanisms are discussed as they relate to the observation of activation and deactivation of normal Raman modes in SERS. Next, experimental conditions that can be used to tune molecular affinity to and density near SERS substrates are summarized and considered while tuning these parameters are conveyed. Finally, successful examples of quantitative SERS detection are discussed, and future opportunities are outlined. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 73 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The Preparation and Characterization of Quantum Dots in Polysaccharide Carriers (Starch/Chitosan) as Elements of Smart Packaging and Their Impact on the Growth of Microorganisms in Food

Nanocomposite materials are increasingly commonly used to ensure food safety and quality. Thanks to their unique properties, stemming from the presence of nanoparticles, they are used to develop advanced sensors and biosensors, e.g., for various harmful substances, heavy metals, microorganism growth, and environmental changes in food products. The aim of this study is to produce novel films based on natural resources-potato starch and chitosan-incorporating generated quantum dots of zinc sulfide and cadmium sulfide. The biocomposites were subjected to the following assays: FTIR spectroscopy, UV-VIS spectroscopy, photoluminescence spectroscopy, and SEM/TEM spectroscopy. Their mechanical properties were also analyzed, a colorimetric analysis was performed, and the water content, solubility, and water absorption capacity were determined. A storage test was also performed, using poultry meat covered with the produced films, to assess the microbiological quality. The results confirmed the presence of the quantum dots in the starch-chitosan matrix. The unique optical properties of the films were also demonstrated. It was shown that the composites with nanoparticles limited the growth of selected microorganisms in poultry meat. The food storage time was found to have an impact on the fluorescent properties of the composites. The results point to the possibility of using the produced films as active and smart packaging.

Versatile and Robust Method for Antibody Conjugation to Nanoparticles with High Targeting Efficiency

The application of antibodies in nanomedicine is now standard practice in research since it represents an innovative approach to deliver chemotherapy agents selectively to tumors. The variety of targets or markers that are overexpressed in different types of cancers results in a high demand for antibody conjugated-nanoparticles, which are versatile and easily customizable. Considering up-scaling, the synthesis of antibody-conjugated nanoparticles should be simple and highly reproducible. Here, we developed a facile coating strategy to produce antibody-conjugated nanoparticles using 'click chemistry' and further evaluated their selectivity towards cancer cells expressing different markers. Our approach was consistently repeated for the conjugation of antibodies against CD44 and EGFR, which are prominent cancer cell markers. The functionalized particles presented excellent cell specificity towards CD44 and EGFR overexpressing cells, respectively. Our results indicated that the developed coating method is reproducible, versatile, and non-toxic, and can be used for particle functionalization with different antibodies. This grafting strategy can be applied to a wide range of nanoparticles and will contribute to the development of future targeted drug delivery systems.

Bio-conjugation of anti-human CD3 monoclonal antibodies to magnetic nanoparticles by using cyanogen bromide: A potential for cell sorting and noninvasive diagnosis

The conjugation of monoclonal antibodies with superparamagnetic iron oxide nanoparticles (SPIONs) has appeared as a potential multifunctional clinical tool, which can effectively diagnose cancers and monitor their treatment, specifically. Despite the presence of different methods for conjugating antibodies to iron oxide nanoparticles, novel cost-effective and simpler conjugation techniques should be performed in this regard. In current study, an anti-CD3 monoclonal antibody was conjugated to the Fe3O4 coated by carboxymethyl dextran (CMD) using cyanogen bromide (CNBr). Moreover, EDC/NHS techniques were applied as a positive control. The experimental results showed that the Conjugation was performed and the presence of the antibody conjugated to the MNPs in human xenograft tumors was confirmed using Prussian blue (PB) staining, following magnetic resonance imaging (MRI), 30 min after injection. This conjugation method was shown to be able to separate CD3+ T lymphocytes efficiently from whole blood with high purity. Accordingly, this type of bio-conjugation method can be utilized in the future for cell sorting, and can be applied for adopted cell therapies such as CAR-T cell (Chimeric antigen receptor T cell) therapy, as well as targeted MRI imaging.

Post-synthetically modified metal-organic frameworks for sensing and capture of water pollutants

Thanks to a bottom-up design of metals and organic ligands, the library of metal-organic frameworks (MOFs) has seen a conspicuous growth. Post-synthetically modified MOFs comprise a relatively smaller subset of this library. Whereas the approach of post-synthetic modification was seminally introduced for MOFs in the early 1990s, the earliest examples of post-synthetically modified MOFs are only congruous with adsorption and catalysis. The utility of PSM-derived MOFs for the sensing and capture of water contaminants is relatively niche. Arguably though, an increasing number of post-synthetically modified MOFs are finding relevance in the context of water pollutant remediation. In this article, we review the recent advances in this area and propose a structure-function relationship-guided blueprint for the future outlook.

Positive Sorption Behaviors in the Ligand Exchanges for Water-Soluble Quantum Dots and a Strategy for Specific Targeting

N,N,N',N'-Tetramethylethylenediamine (TMEDA) and ethylenediamine (EDA) were investigated in-depth in the ligand exchanges for water-soluble CdSe quantum dots (QDs). TMEDA could assist the phase transfer of QDs from apolar solvents to the aqueous solutions as stabilized by mercaptopropionic acid (MPA). We successfully maintained the stability of a series of MPA-capped QDs of different ligand densities for NMR characterizations in aqueous solutions. The proton NMR spectroscopies of MPA of the binding state were used to analyze the ligand densities on the surface of QDs, which were not explored in the past. The binding thermodynamics of the surface ligands of QDs, as analyzed using the Hill equation, demonstrated a positive promoting effect and possible interactions between ligands. EDA in the purification process underwent a spontaneous adsorption with two-stage thermodynamic behaviors as characterized by isothermal titration calorimetry. Due to the positive role of the already adsorbed ligands, excess EDA would further attach to the surface of QDs in the form of non-bonded physisorption, greatly improving the quantum yield (QY) of QDs, and the ligand of this part would almost not change the stability of QDs. We proposed a strategy for the preparation of aqueous QDs with a high QY, followed by fluorescence quenching-enhancement cycles caused by purification-adsorption operations. The strategy made it possible for the preparation of functional QDs with small molecules after purification operations. Kinetics of the sorption of ligands on the surface of QDs were determined by fluorescence spectroscopy. Modified pseudo-second-order kinetics after consideration of the ligand-ligand interaction effect could well analyze the kinetic data. This kinetic model had advantages over the previous ligand exchange model in terms of accuracy, reproducibility, and physical significance. Finally, we used the above strategy for the design of fluorescent QDs for bioimaging of lysosomes, mitochondria, and cancer cells. This work can simplify the preparation of multifunctional fluorescent QDs and avoid complicated ligand design.