**5. Particle-Based Therapeutics**

Chemodynamic therapy (CDT) has received extensive research attention in recent years. However, the efficiency of CDT is influenced by H2O2 limitations in the tumor. In this issue, Dr. Yang Shu and her collaborators [9] described a novel core–shell nanostructure, namely a Cu-metal organic framework (Cu-MOF)/glucose oxidase (GOD)@hyaluronic acid (HA) (Cu-MOF/GOD@HA), for the purpose of improving CDT efficacy by increasing H2O2 concentration and cancer cell targeting. The CDT enhancement as a result of GOD and HA effects in Cu-MOF/GOD@HA was confirmed for both in vitro cell and in vivo animal studies.

Photothermal therapy has been widely tested in treating bacterial infections [10,11]. Weiwei Zhang et al. [12] tested the growth inhibition of Staphylococcus aureus by using a very low concentration of vancomycin and applying photothermal therapy with MoS2. MoS2-Van-FITC with near-infrared irradiation significantly inhibited S. aureus growth, reaching an inhibition rate of 94.5%, indicating its possible use as a wound-healing agent.

Dr. Oleg A. Yeshchenko et al. [13] presented the thermoresponsive Zinc-TetraPhenyl Porphyrin-based hybrid nanosystem. The shrinking of D-g-PNIPAM macromolecules during a thermally induced phase transition leads to the release of both ZnTPP molecules and Au NPs from the ZnTPP/D-g-PNIPAM/AuNPs macromolecule. The three-fold enhancement of singlet oxygen production with surface plasmon resonance is critical for clinic applications.

#### **6. New Materials and Structures**

Bovine-serum-albumin-embedded Au nanoclusters are thoroughly investigated by Radek Ostruszka [14] using continuous-wave electron paramagnetic resonance, lightinduced EPR, etc. In addition to the presence of Au(0) and Au(I) oxidation states in BSA-AuNCs, a significant amount of Au(II) was detected, which may come from a disproportionation event occurring within NCs: 2Au(I) − Au(II) + Au(0).

Haibin Li et al. [15] reported on n-p Bi2O2CO3/α-Bi2O3 heterojunction microtubes and studied their photocatalytic activities under visible-light irradiation. The results indicated that Bi2O2CO3/α-Bi2O3 with a Bi2O2CO3 mass fraction of 6.1% exhibited higher photocatalytic activity than α-Bi2O3.

Obtaining drinking water from seawater has always been a long-term goal. Here, Dr. Zhongxin Liu et al. [16] reported on the use of graphene-loaded nonwoven fabric membranes coated with graphene oxide for seawater purification. The photothermal membrane is expected to be suitable for regional water purification and seawater desalination due to its high light absorption, strong heating effect, and its evaporation rate, which is about five times higher than that of non-woven fabric.

In this issue Dr. Yiqun Li et al. [17] synthesized a novel carboxymethylcellulose– polyaniline-film-supported copper catalyst (CuII/I@CMC-PANI) and used it as a dip catalyst for aldehyde–alkyne–amine coupling reactions with a high yield of 97%. They found that CuII/I@CMC-PANI, as a good dip catalyst, is very useful in organic synthesis due to its easy fabrication, convenient deployment, superior catalytic activity, and high reusability.

We would like to thank the *Nanomaterials* Editorial Office for the opportunity to edit this Special Issue, as well as all the authors for their valuable contributions and reviewers for their valuable comments. This Special Issue would not have been possible without them. We hope that this Special Issue can offer some valuable information and guidance for future research directions.

**Conflicts of Interest:** The authors declare no conflict of interest.
