Targeted drug delivery

Targeted drug delivery approaches

Nanomedicine is one of the most likely and advanced approaches in the development of cutting-edge cancer treatment. Cancer therapy is a very broad medical field with various treatment approaches. One possibility is the usage of nanoparticles. They can kill tumor cells either directly (e.g., via oxidative stress or DNA damage), or they act as carriers for anti-tumor agents. Using such a nanocarrier approach enables therapeutic agents to infiltrate efficiently and exclusively into tumor tissue via passive or active targeting resulting in diminished side effects in normal tissue.

Targeted drug delivery is a promising approach for cancer treatment that has the potential to improve the efficiency and safety of chemotherapy. While there are still challenges to overcome, such as ensuring the safety and effectiveness of these materials, targeted drug delivery has the potential to revolutionize cancer treatment and improve the lives of millions of people. In this technique, it uses nanoparticles to deliver drugs directly to specific cells or tissues in the body, such as cancer cells. This approach has several advantages over traditional drug delivery methods, including increased drug ability, reduced side effects, and improved patient outcomes.

Selective targeting: Nanoparticles can be designed to selectively target cancer cells by attaching targeting molecules to their surface, such as antibodies or peptides. These targeting molecules recognize and bind to specific proteins or receptors that are overexpressed on the surface of cancer cells, enabling the nanoparticles to deliver drugs directly to the tumor.

Controlled release: Once the nanoparticles have reached the tumor, they can release the drugs in a controlled manner, providing sustained drug release over a longer period. This reduces the frequency of drug administration and minimizes toxic side effects.

Increased drug efficacy: Targeted drug delivery can increase the efficacy of cancer treatment by delivering drugs directly to the tumor, where they are needed most. This approach can also reduce the drug dose required to achieve the desired effect, reducing the risk of toxicity and side effects.

Improved patient outcomes: Targeted drug delivery can improve patient outcomes by reducing the likelihood of drug resistance and improving the overall response to treatment. This approach can also improve the quality of life for cancer patients by reducing the side effects of chemotherapy.

Nanoparticles for targeted drug delivery

Nanoparticles are used in targeted drug delivery because of their unique properties, such as their small size, large surface area, and ability to encapsulate a variety of drugs. nanoparticles offer many advantages for drug delivery, including improved drug efficacy, reduced side effects, and targeted drug delivery. While there are still challenges to overcome, such as ensuring the safety and effectiveness of these materials, nanoparticle-based drug delivery has the potential to revolutionize medicine and improve the lives of millions of people.

Liposomes: Liposomes are spherical particles made up of a phospholipid bilayer that can encapsulate both hydrophilic and hydrophobic drugs. They can also be modified with targeting molecules to selectively deliver drugs to specific cells or tissues.

i.e., To achieve true targeted delivery, liposomes must be modified on their surface with an agent that confers specificity. One possible approach is the conjugation of glycoproteins, antibodies, antibody fragments, or single-chain antibodies to the liposomal surface.

Polymeric nanoparticles are made up of biodegradable polymers and can be designed to release drugs in a controlled manner. As well Dendrimers are branched, tree-like molecules that can encapsulate drugs and release them in a controlled manner. They can also be modified with targeting molecules to improve their specificity and effectiveness.

Carbon nanotubes (CNTs): are cylindrical structures made up of carbon atoms that can be functionalized with drugs and targeting molecules. They have a high surface area and can penetrate cell membranes, making them useful for intracellular drug delivery. They have been studied for their potential use in cancer treatment. These tiny tubes made of carbon atoms have unique properties that make them attractive for medical applications. CNTs can be used to target cancer cells while leaving healthy cells unharmed. By attaching CNTs that bind specifically to cancer cells, one can detect the presence of cancer cells in the body. Even though CNTs have shown promise in laboratory studies, more research is needed to determine their safety and effectiveness in humans before they can be used in cancer treatment.

Gold nanoparticles (Au NPs): Gold nanoparticles can be used to deliver drugs and imaging agents, as they have unique optical and electronic properties. They can also be modified with targeting molecules to improve their specificity and efficacy.

They have the potential to improve the effectiveness of cancer treatment and reduce its side effects. While there are still challenges to overcome, such as ensuring the safety and efficacy of these materials, gold nanoparticles offer a promising approach for cancer treatment that could revolutionize medicine and improve the lives of millions of people. Specifically, Functionalized Au NPs exhibit good biocompatibility and controllable biodistribution patterns, which make them particularly fine candidates for the basis of innovative therapies. They are stable, nonimmunogenic and low toxicity in vivo. In addition, they can accumulate in the tumor sites due to the EPR effect so they are attractive in imaging diagnosis.

In targeted drug delivery, Au NPs can be functionalized with targeting molecules, such as antibodies or peptides, that recognize and bind to specific proteins or receptors on the surface of cancer cells. Once bound, the nanoparticles can deliver drugs directly to the tumor, increasing drug efficacy and reducing side effects.

As well in photothermal therapy, Au NPs are activated by light, causing them to generate heat and destroy cancer cells while avoiding damage to other tissues. This approach is particularly effective for solid tumors, where the nanoparticles can be injected directly into the tumor and activated using a laser. After being irradiated by light, the Au plasmonic nanoparticles are delivered to the tumor cells, where the absorbed light is converted into heat, causing irreversible damage to the surrounding pathological tissues.

Au NPs can be used as imaging agents to detect and diagnose cancer. They have unique optical properties that allow them to be detected using various imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI). It also enhances the effectiveness of radiotherapy by acting as radiation sensitizers. They can increase the absorption of radiation by cancer cells, leading to increased cancer cell death and improved patient outcomes.

References

https://pharma.unibas.ch/de/research/research-groups/pharmaceutical-technology-2253/research/drug-targeting/engineered-nanomaterials-for-drug-targeting/different-delivery-systems-liposomes-polymer-nps-silica-iron/

Nanomedicine review: clinical developments in liposomal applications

Tips for approaching physics problems

Approaching physics problems can be intimidating but breaking them down into smaller parts and applying problem-solving strategies can make them more manageable.

Draw a diagram: A diagram can help you visualize the problem and identify any relevant physical principles. Label the diagram with the knowns and unknowns and use it to guide your solution.

Choose an appropriate strategy: Depending on the problem, you may need to use different strategies to solve it. For example, if the problem involves motion, you may need to use kinematic equations, while if it involves forces, you may need to use Newton's laws.

Solve the problem: Once you have identified the strategy to use, apply the relevant equations and concepts to solve the problem. Make sure you keep track of units and show all your work.

Check your answer: After you have solved the problem, double-check your answer to make sure it makes sense and is consistent with the problem statement. Check units and significant figures.

Practice, practice, practice: The more physics problems you solve, the more comfortable you will become with the process. Look for opportunities to practice and seek feedback from your instructor or peers.

Screw Gauge

Screw gauge is an instrument which works based on the principle of micrometer screw. When the width of the material to be measured is close to 0.01mm, screw gauge is used. Screw gauges are typically used to measure diameter of wires/rods, also used to measure thickness of metal sheet and so on. In a standard screw, each thread is separated by a predetermined distance and the thread separation equals the distance traveled by a screw in forward direction in one complete rotation. In other words, when a screw is rotated in a nut, the distance moved by the tip of the screw is directly proportional to the number of rotations.

Parts of screw gauge

• The Screw Gauge consists of a ‘U’ shaped metal frame

• A hollow cylinder is attached to one end of the frame

• Pitch Scale-Sleeve

• Thimble -Head/Circular scale

• Ratchet

• S1-spindle

• S2-Anvil

Pitch of the Screw gauge

Pitch refers to the linear distance between a screw's threads (1mm or 0.5mm).

Pitch scale

It is a scale running parallel to the axis of the screw. It is marked in mm. The spindle of the screw passes through the sleeve cylinder

Thimble/Head scale

The screw is connected to a hollow cylinder which rotates along with nut on turning. i.e., thimble. It is a circular scale marked in mm, attached to the screw. The thimble of a screw gauge has 50 divisions for one rotation. The spindle advances 1mm when the screw is turned through two rotations.

Least Count of a Screw Gauge

The least count of screw gauge is 0.01mm which indicates that one can measure the dimension in steps of 0.01mm.

Least Count can be defined as the minimum value measured by a screw gauge.

In screw gauge with 0-50 division on head scale

Least count =0.5/50=0.01mm

Errors in a screw gauge

To get accurate readings, these unmercenary errors should be avoided.

Zero Error of a Screw Gauge

If the zero of the head scale coincides with the pitch scale axis, there is no zero error.

n-number of divisions

Zero Error Z.E = (n x L.C) = (0 x 0.01)

Zero Correction, Z.C = 0 mm

Positive Zero Error

If the zero of the head scale lies below the pitch scale axis, the zero error is positive.

Eg., 7 th division of the head scale coincides with the pitch scale axis. then the zero error is positive) and is given by,

Z.E = + (n x L.C)= + (7 x 0.01)

Zero Correction Z.C = – (7 x 0.01) =-0.07mm

Negative Zero Error

If the Zero of the head scale lies above the pitch scale axis, the zero error is negative. E.g., 48 th division coincides with the pitch scale axis, then the zero error is negative and is given by,

Z.E = – (50 – 48) x 0.01

Zero Correction Z.C = + (50 – 48) x 0.01=+0.02mm