NPG Asia Materials

Biological lipid membranes for on-demand, wireless drug delivery from thin, bioresorbable electronic implants
Lee CH, Kim H, Harburg DV, Park G, Ma Y, Pan T, Kim JS, Lee NY, Kim BH, Jang KI, Kang SK, Huang Y, Kim J, Lee KM, Leal C and Rogers JA
On-demand, localized release of drugs in precisely controlled, patient-specific time sequences represents an ideal scenario for pharmacological treatment of various forms of hormone imbalances, malignant cancers, osteoporosis, diabetic conditions and others. We present a wirelessly operated, implantable drug delivery system that offers such capabilities in a form that undergoes complete bioresorption after an engineered functional period, thereby obviating the need for surgical extraction. The device architecture combines thermally actuated lipid membranes embedded with multiple types of drugs, configured in spatial arrays and co-located with individually addressable, wireless elements for Joule heating. The result provides the ability for externally triggered, precision dosage of drugs with high levels of control and negligible unwanted leakage, all without the need for surgical removal. and investigations reveal all of the underlying operational and materials aspects, as well as the basic efficacy and biocompatibility of these systems.
Aptamer-conjugated nanomaterials for specific cancer cell recognition and targeted cancer therapy
Liu Q, Jin C, Wang Y, Fang X, Zhang X, Chen Z and Tan W
Based on their unique advantages, increasing interest has been shown in the use of aptamers as target ligands for specific cancer cell recognition and targeted cancer therapy. Recently, the development of aptamer-conjugated nanomaterials has offered new therapeutic opportunities for cancer treatment with better efficacy and lower toxicity. We highlight some of the promising classes of aptamer-conjugated nanomaterials for the specific recognition of cancer cells and targeted cancer therapy. Recent developments in the use of novel strategies that enable sensitive and selective cancer cell recognition are introduced. In addition to targeted drug delivery for chemotherapy, we also review how aptamer-conjugated nanomaterials are being incorporated into emerging technologies with significant improvement in efficiency and selectivity in cancer treatment.
Guiding nanomaterials to tumors for breast cancer precision medicine: from tumor-targeting small-molecule discovery to targeted nanodrug delivery
Qu X, Qiu P, Zhu Y, Yang M and Mao C
Precision medicine emphasizes patient-specific formulation for treatment of diseases, especially cancer. However, in targeted cancer treatment, because the expression level of tumor receptors in each patient varies even for the same type of cancer, the ligand/receptor-mediated approach does not seem promising for precision medicine. In this work, we demonstrated our strategy of using a phage display technique for breast cancer precision medicine. Using biopanning, we first selected an MCF-7 breast tumor-targeting peptide, then tested the effectiveness of the as-selected peptide in tumor homing and finally conjugated the peptide to a model photothermal drug, namely, gold nanorods, to achieve enhanced cancer killing efficacy. The peptides identified by the phage display technique can guide the drug to the tumors without the need to know the exact receptors on the tumor. This approach requires significantly less effort to explore patient-specific targeting molecules for precision medicine.
Built-in microscale electrostatic fields induced by anatase-rutile-phase transition in selective areas promote osteogenesis
Ning C, Yu P, Zhu Y, Yao M, Zhu X, Wang X, Lin Z, Li W, Wang S, Tan G, Zhang Y, Wang Y and Mao C
Bone has a built-in electric field because of the presence of piezoelectric collagen. To date, only externally applied electric fields have been used to direct cell behavior; however, these fields are not safe or practical for use. In this work, for the first time, we use a periodic microscale electric field (MEF) built into a titanium implant to induce osteogenesis. Such a MEF is generated by the periodic organization of a junction made of two parallel semiconducting TiO zones: anatase and rutile with lower and higher electron densities, respectively. The junctions were formed through anatase-rutile-phase transition in selective areas using laser irradiation on the implants. The and studies confirmed that the built-in MEF was an efficient electrical cue for inducing osteogenic differentiation in the absence of osteogenic supplements and promoted bone regeneration around the implants. Our work opens up a new avenue toward bone repair and regeneration using built-in MEF.
Engineering protein nanocages as carriers for biomedical applications
Bhaskar S and Lim S
Protein nanocages have been explored as potential carriers in biomedicine. Formed by the self-assembly of protein subunits, the caged structure has three surfaces that can be engineered: the interior, the exterior and the intersubunit. Therapeutic and diagnostic molecules have been loaded in the interior of nanocages, while their external surfaces have been engineered to enhance their biocompatibility and targeting abilities. Modifications of the intersubunit interactions have been shown to modulate the self-assembly profile with implications for tuning the molecular release. We review natural and synthetic protein nanocages that have been modified using chemical and genetic engineering techniques to impart non-natural functions that are responsive to the complex cellular microenvironment of malignant cells while delivering molecular cargos with improved efficiencies and minimal toxicity.
Spin-wave propagation in cubic anisotropy materials
Sekiguchi K, Lee SW, Sukegawa H, Sato N, Oh SH, McMichael RD and Lee KJ
The information carrier of modern technologies is the electron charge whose transport inevitably generates Joule heating. Spin-waves, the collective precessional motion of electron spins, do not involve moving charges and thus avoid Joule heating [1-3]. In this respect, magnonic devices in which the information is carried by spin-waves attract interest for low-power computing. However implementation of magnonic devices for practical use suffers from low spin-wave signal and on/off ratio. Here we demonstrate that cubic anisotropy materials can enhance spin-wave signals by improving spin-wave amplitude as well as group velocity and attenuation length. Furthermore, cubic anisotropy material shows an enhanced on/off ratio through a laterally localized edge mode, which closely mimics the gate-controlled conducting channel in traditional field-effect transistors. These attractive features of cubic anisotropy materials will invigorate magnonics research towards wave-based functional devices.
Phase stabilization of cesium lead iodide perovskites for use in efficient optoelectronic devices
Jin H, Zeng YJ, Steele JA, Roeffaers MBJ, Hofkens J and Debroye E
All-inorganic lead halide perovskites (LHPs) and their use in optoelectronic devices have been widely explored because they are more thermally stable than their hybrid organic‒inorganic counterparts. However, the active perovskite phases of some inorganic LHPs are metastable at room temperature due to the critical structural tolerance factor. For example, black phase CsPbI is easily transformed back to the nonperovskite yellow phase at ambient temperature. Much attention has been paid to improving the phase stabilities of inorganic LHPs, especially those with high solar cell efficiencies. Herein, we discussed the origin of phase stability for CsPbI and the strategies used to stabilize the cubic (α) phase. We also assessed the CsPbI black β/γ phases that are relatively stable at nearly room temperature. Furthermore, we determined the relationship between phase stabilization and defect passivation and reviewed the growing trend in solar cell efficiency based on black phase CsPbI. Finally, we provide perspectives for future research related to the quest for optimum device efficiency and green energy.
Atomic scale determination of magnetism and stoichiometry at the LaSrMnO/SrTiO interface: investigation of inverse hysteresis
Panchal G, Stramaglia F, Kumar P, Schierle E, Habicht K, Vaz CAF and Fritsch K
Controlling the correlations and electronic reconstruction at the interface of transition metal oxide heterostructures provides a new pathway for tuning their unique physical properties. Here, we investigate the effects of interfacial nonstoichiometry and vertical phase separation on the magnetic properties and proximity-induced magnetism of epitaxial LaSrMnO (LSMO)/SrTiO(001) oxide heterostructures. We also reinvestigate the recently observed inverse hysteresis behavior reported for this system, which we find emanates from the remanent field of the superconducting solenoid and not from antiferromagnetic intra-layer exchange coupling in low coercivity LSMO thin films. Combined atomically resolved electron energy loss spectroscopy, element-specific X-ray magnetic circular dichroism, and interface-sensitive polarized soft X-ray resonant magnetic reflectivity show the formation of a Mn-enriched interfacial LSMO layer, of a Ti-derived magnetic interface layer coupled ferromagnetically to LaSrMnO, together with a small density of O-vacancies at the interface. These results not only advance the understanding of the magnetism and spin structure of correlated oxide interfaces but also hold promise for practical applications, especially in devices where the performance relies on the control and influence of spin polarization currents by the interfacial spin structure.
Microneedles for controlled and sustained intraocular drug delivery
Lee J, Jeong J, Nguyen VP, Hong S, Paulus YM and Lee CH
Microneedles (MNs) have emerged as a promising technology for minimally invasive drug delivery, offering significant advantages in the treatment of ocular diseases. These miniaturized needles enable precise, localized drug delivery directly into specific tissues of the eye, such as the cornea, sclera, vitreous, or retina, while minimizing pain and discomfort. MNs can be fabricated from various biocompatible materials, including metals, silicon, and biodegradable polymers, making them highly adaptable to various clinical applications. Recent advancements in MN design include the integration of 3D printing technologies to create highly customized geometries for improved drug delivery precision, the use of smart materials that enable stimuli-responsive and sustained drug release, and the development of hybrid microneedles combining different polymers to enhance both mechanical strength and controlled drug release. These innovations have established MNs as a superior alternative to traditional methods like eye drops or intravitreal injections, which often face issues of limited bioavailability and patient compliance. This review summarizes the current state of research on MN-based ocular drug delivery, focusing on material developments, fabrication methods, drug release mechanisms, and implantation techniques. Future directions for MN technology in ophthalmology are also discussed, highlighting its potential to improve treatment outcomes for complex ocular diseases.