Microbial Interactions at Nanobiotechnology Interfaces. Группа авторов
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СКАЧАТЬ location by loading in mesoporous silica NMs (Qi et al., 2013). The prerequisite for effective target therapy is to target macrophages with NMs, make macrophages active, and then release the drug (Xiong et al., 2012).

      4 Controllability: As mentioned above, the controlled release of any drug is crucial for its action mechanism. Conventional delivery methods failed to maintain controlled and sustained release of many drugs. This resulted in either high drug levels for short time periods or very low drug levels. Thus, repeated dosage is given, which has its own side effects. NMs' ability to slowly release the drugs at therapeutic concentration results in reduced frequency of dosing and pain. The prolonged drug release from NM‐based delivery systems provides better inhibitory effects on microbial growth (Liu, Zhang, Li, Yang, Pan, Kong, & Zhang, 2016).Further, the drug release from NMs can also be controlled by making them responsive to various stimulatory factors like temperature, pH, light, chemicals, or magnetic field (Lim, Chung, & Chung, 2018; Wu et al., 2016). Similar systems are already being explored for better controlled drug release. For example, drugs like levofloxacin are delivered using solid–lipid NMs, which prolong the retention for ocular applications (Baig et al., 2016).

      5 Combination: Another important advantage of NM‐based drug delivery is its ability to deliver multiple drugs at the same time through the same channel. In many cases, the targeted site of infection has multiple microbes present, requiring the delivery of specific drugs for each type. In such cases, multiple drugs can be packed and delivered using same NMs. Also, for single‐cell type, it is difficult to develop resistance to multiple antibiotics that are delivered through same NM at the same time. Multiple action mechanisms make this kind of system more efficient.

      On the other hand, two or more types of NMs can also be combined to overcome the disadvantages of a single type of NM. The much explored liposome‐based drug delivery system has a short shelf life, less stability, and low encapsulation efficacy. This system can be combined with other delivery systems like solid lipid NMs to obtain hybrid NM with improved properties. Another example of a hybrid NM delivery system are lipid–polymer NMs with better efficacy (Hadinoto, Sundaresan, & Cheow, 2013).

      1.7.1 Nanometals

      Metals over a threshold concentration exhibit toxicity on the biological system. Among them, heavy metals such as arsenic, cadmium, chromium, lead, and mercury are highly toxic to the living system (Tchounwou et al., 2012). The property of metal toxicity has been exploited to prepare antibacterial nanometals that are toxic to bacterial cells. An additional advantage of nanometals is the possibility of tuning the properties of the system during the synthesis phase.

      1.7.2 Metal Oxides