PSAT Reading Practice Test 1

Questions 1-10 refer to the following information.

Passage 1
The technology of drug delivery is one of
the most important in the field of medicine and
biomedical engineering. The more site-specific
a delivery system is, the more effective the drug
05it is delivering will be; the more conservative a
delivered drug dosage is, the less severe the side
effects will be. This is especially true of different
drugs used to predominantly treat infections and
cancers. A new technology called electrostatic
10processing, or electrospinning, accomplishes
both of these goals.
Electrospinning creates biodegradable scaffolds
composed of fibers ranging from nanometers
to micrometers in diameter, an attribute that is
15intrinsically difficult to obtain from other fiber-
fabrication processes. The electrospinning process
begins with a polymer solution at a prescribed
charge and viscosity that is pumped through a
spinneret. An electric field, powered by a high
20voltage power supply, is applied to this spinneret
so that a droplet is formed at the tip of the
spinneret. This droplet morphs into the shape
of a cone, in which the surface tension of the
droplet is counterbalanced by the applied external
25electrostatic forces. Once the applied voltage is
strong enough to overcome the droplet's surface
tension, a fibrous jet is emitted from the cone
and captured on a grounded collecting plate. The
distance between the spinneret and the collecting
30plate is where any residual solvent in the ejected
jet stream evaporates, resulting in a collection of
non-woven submicron-sized fibers that, ultimately,
form a highly porous scaffold. Drug delivery
via these electrospun scaffolds affords ample
35flexibility in creating an optimal delivery vehicle
for therapeutic treatment.
The chemical properties of the materials
utilized as base polymers determine how stable
the electrospun scaffolds are and how well they
40function. Both synthetic and natural materials
can be used as base polymers. Between the
two, natural polymers typically possess lower
levels of toxicity, immunogenicity, and improved
biocompatibility. In other words, natural polymers
45have a greater ability to perform more effectively
than synthetic polymers do in the treatment
of human disease. Examples of a natural base
commonly used as a base for electrospun fibers
include collagen and elastin. Collagen is the most
50prevalent protein in the extracellular matrix
(ECM) of soft and hard tissues, and collagen
types I, II, and III have all been utilized as the
main component of electrospun scaffolds. Elastin
has also been substantially utilized as a polymer
55in electrospinning, especially for vascular tissue
engineering. Beyond the inherent advantages
that natural polymers possess, the combination of
natural polymers can sometimes provide a greater
benefit toward constructing an ideal electrospun
60scaffold. For example, the combination of
collagen and elastin in certain ratios has been
demonstrated to produce ideally-sized fiber
diameters. Thus, the potential to combine—or
include—other natural polymers is tremendous
65in attempting to engineer a drug delivery vehicle
with optimal biodegradable properties.
Passage 2
Although it has historically been the case that
natural polymers were favored in the construction
of electrospun fibers for drug delivery systems,
70there is a growing trend towards employing
synthetic polymers. Synthetic polymers are used
to enhance various characteristics of the drug
delivery system goals. These characteristics include
degradation time, mechanical properties, and cell
75attachment affinities. Synthetic polymers are able
to improve these characteristics as they are more
easily tailored to a wider range of properties such
as hydrophilicity and hydrophobicity—in other
words, the desired solubility of an electrospun
80scaffold. Because synthetic polymers can be
created in laboratories, a nearly innumerable
number of possible products that are made from
synthetic polymers can be engineered to address
any particular clinical need. The most popular of
85these are the most hydrophobic and biodegradable
polymers such as poly(glycolide) (PGA) and
Despite the clear benefits of synthetic
polymers when compared with natural
90polymers, it is of the utmost importance to not
limit scientific or medical pursuit by a purist
approach. The ability to blend the variety of
synthetic polymers with the strong biocompatible
properties of natural polymers may allow
95biomedical engineers to more precisely fine-tune
the properties of electrospun scaffolds. It is this
wide-ranging flexibility of polymer compositions
that gives electrospun scaffolds such huge
promise in medical applications, causing the
100huge spike of research done in this space in the
last several decades. With even more to discover,
it is both likely and lucky that this interest will
continue for some time.

10 questions    13 minutesAll test questions

1. The author mentions infections and cancers (lines 8–9) in order to

2. In Passage 1, the reference to "nanometers to micrometers" (lines 13–14) serves to

3. As used in line 30, "residual" most nearly means

4. In discussing the nature of natural polymers, the author of Passage 1 suggests that

5. In Passage 2, the connection between natural and synthetic polymers is best described in which of the following ways?

6. The second paragraph of Passage 2 primarily serves to

7. From the information presented in Passage 2, it can be inferred that

8. The authors of both passages would most likely agree with which of the following?

9. The passages differ in that Passage 1

10. What is the primary difference in the tones of Passages 1 and 2 with respect to their arguments regarding natural versus synthetic polymer bases?

All content of site and practice tests © 2022 Jack.
Quick View

PSAT Practice Tests

More Information